
<6 <2* 












> 

w 







V— > V N 



<L1> _ l 



"V 



% 



^ 



* rCV\ »8 /A o NP_ ^YV V * c{\\ W /A o ^n .aX v ^ . 



%.<? 



CP<\ V = 






^0< 










^ 










&<*> 




O.L^W 



* ■ $ 




'••^ A^ 








9s. *<>. * 






w 

<£ ^ 

£ ^ 



^ tf 

^Kr 



^ ^ -• IPSO ° 4 ? ^ 

^ ' * * s s A^ _ <*> * * * s 










W Vrf 



^° *ii 




cv t s * * r *y^ 



^ 









r 











<6 a 














^ V 






^Vc? 




"^o* 



J* 



^ °* °^$ 



<^\ \! *f<& K/ , ;. . v ; ^. 



^ ^ o , v • 



THE WORLD: 

OR 

FIRST LESSONS 



ASTEONOMY AND GEOLOGY, 

IN CONNECTION - WITH THE PRESENT AND PAST CONDITION OF 

OUR GLOBE, 



BY HA3ULTOX £. S^IITH, A. OT* 




SHELL LIMESTONE, FROM THE MOUTH OF THE THAMES. 

(From MantelVs Medals of Creation). 



" The World is God's Epistle to Mankind."— Plato. 

CLEVELAND: 
M. C. YOUNGLOVE AND COMPANY. 

1848. 






Entered according to Act of Congress, in the year 1848, 

Bt HAMILTON L. SMITH, 

In the Clerk's Office of the District Court of the District of Ohio. 



6h $ t (f§l 



X 



I h 






PREFACE. 



The importance of the sciences of Astronomy and Geology, 
is acknowledged by every one. Few, however, find sufficient 
leisure to bestow upon these subjects much attention. They look 
upon the ponderous tomes which men of science have from time 
to time prepared, with a sort of indifference, as too learned for 
them. And yet, show any of these, a curious star in the 
heavens ; tell them of the wonders revealed by the telescope; ex- 
hibit to them, the impression of a fish in sandstone, or chalk; or 
show them through a microscope, the curious and distinctive 
structure of fossil teeth, or the infusoria in a fragment of flint ; 
and they will give willing attention. Since, then, the subjects 
themselves are so interesting, so profitable, and withal harmless, 
we have endeavored — with what success will hereafter appear — 
to supply a desideratum long felt. The object of the present 
volume is to present in a popular manner, so much of Astrono- 
my, Meteorology, and Geology, as seemed desirable for everyone 
to know. While no pretensions are made to scientific accuracy, 
yet it is believed that the book will be found worthy of an atten- 
tive perusal. There is little to be gained by merely glancing here 
and there at a page; the knowledge thus obtained* if any, will be 
small, and^soon lost. The attentive reader will* if the book be 
worth perusing at all, find sufficient to amply repay for the time 
thus spent. It should hardly be necessary for any one at this late 
day, to offer an apology in behalf of Geological studies, because 
of the fancied contradictions to the Mosaic chronology. Writers on 
this subject heretofore, have spent no little pains, in what we may 
well term, endeavoring to "make darkness visible." So apolo- 
gies were once offered for Astronomy, when that noble science 
taught the diurnal and annual motions of the earth. We have 
felt called upon to make no such apology, but simply to state the 



PREFACE. 



facts, well convinced that true philosophy and religion go hand in 
hand, and that if *' an undevout astronomer is mad," so must be 
an undevout geologist How vast, and how ennobling the ideas 
of Creative Power and Wisdom, which these sister sciences af- 
ford. The mind is overwhelmed by the immensity of creation, 
whether it strives to reach beyond the faintest and fartherest star 
yet discovered through optic glass, or whether it endeavors to 
reckon the years elapsed since the first granite rocks upreared 
their rugged steeps amid the primeval waters. Though we have 
gazed for whole nights at those dim streaks of nebulous matter in 
the heavens, at the planets, and revolving stars, when there were 
companions with us, no longer upon earth ; and though we have 
split open the sandstone shales, and picked out the fossil shells, and 
looked for hours at little fragments of fossils through the micro- 
scope, we do not feel our time as wasted, or wholly spent in vain, 
if we may be the means of communicating to others a knowledge 
of these pleasant subjects. However imperfect the execution of 
our work may be, yet to it we have given long and patient atten- 
tion. We cannot claim much merit for originality. Among the 
host of scientific men whose lives have been spent in original in- 
vestigations, it would be strange could we not find better illustra- 
tions than our own ; we are still but learners. 

Should the present attempt to produce a popular work upon 
Astronomy and Geology prove successful, it is anticipated follow- 
ing it up with a volume upon the planets and stars ; for in the 
present, only so much of Astronomy is presented as is necessary 
to understand the motions and general phenomena of our earth. 
The chapters on fossil remains are not as many as might seem 
desirable; perhaps we may more perfectly and fully review the 
same subjects hereafter in another volume. 

It is but right to say that the engravings have all been executed 
in this city by Mr. J. Brainerd; and when we add that they are 
not from transfers, out from pencil drawings, they will be ac- 
knowledged as very creditable specimens of the artist's skill. 

Cleveland, August, 1848. 



INTRODUCTION. 



It would be difficult for us to name a study more interesting 
than a history of the Earth, past and present ; for by a peculiar 
and distinct chain of causation, it unites the present with the re- 
mote past; constantly urges us to look for the beginning of that 
state of things we have been contemplating; conducts us to the 
boundaries of physical science, and even gives us a glimpse of 
the regions beyond. 

The Astronomer looks upon the heavens as the type of eternity 
and immortality. The crystal spheres and orbs which he once 
imagined to exist, are, so far as stability and uniformity are con- 
cerned, now no longer necessary. A few simple motions, results 
of one law, controled by one Power Divine, sustains the mighty 
fabric. The Geologist looks upon the heavens and upon the 
earth as but everlasting; he comprehends that a thousand changes 
may come over them, while still they move in their grand circles. 
* To him the present configuration of land and sea is but one of the 
many changes through which the globe has passed, and he is 
prepared to admit that the whole human race may be swept away, 
and a new creation succeed ; — such catastrophes have occurred. 
We ask in vain, whether other worlds are inhabited ; no voice 
comes from those distant orbs to tell us of life , no eye can pene- 
trate so far; we turn then with a renewed zeal to study "the sci- 
ence of the changes which have taken place in the organic and 
inorganic kingdoms of nature,' » as developed on the surface of 
our own planet. The beginning; where shall the beginning be ? 
We endeavor in vain to penetrate the almost sepulchral stillness 
and darkness of the primeval world, and trace with certainty the 
origin of things. All that we can possibly know is the simple 



Viii INTRODUCTION. 

truth — "In the beginning, Jehovah created the heavens and the 
earth." Certainly there was a day — Geology demonstrates this 
— when nothing but barren rock and wide spread waters covered 
the globe. Who but Jehovah called into being the successive 
races of animal and vegetable life, which have flourished and 
died ? Whose eye but Jehovah's has seen the myriads of revo- 
lutions* during which the immense fossil-bearing beds were de- 
posited ? We cannot comprehend these things; 

"Our noisy years seem moments in the being 
Of the eternal silence.' * 

The granite pebble which we roll over, heedless and careless, 
is older by millions of years than the first created of our race; and 
when was that being created ? Questions like this, we are forced 
to say, we can no more answer, than we can tell the form, and 
number, of the inhabitants of the evening star. 

"But though philosophers have never yet demonstrated, and 
perhaps never will be able to demonstrate, what was that primitive 
state of things in the social and material worlds from which the 
progressive* state took its first departure ; — they can still, in all 
the lines of research, go very far back ; — determine many of the 
remote circumstances of the past sequence of events ; — ascend 
to a point which from our position at least, seems to be near the 
origin ; — and exclude many suppositions respecting the origin it* 
self.*' And this is the boundary of human knowledge. 



TABLE OF CONTENTS, 



PART' I 



CHAPTER I. 

Page. 
Rotundity of the Earth — Apparent motion of the Sun— An- 
gles — Measurement of a Degree, - - - - 13 

CHAPTER II. 

Apparent motions of the Planets — Ptolemaic System — 
Measurement of Angles — Diurnal revolution of the Earth 
— Copernican System — Phases of Venus — Religion and 
Philosophy, 25 

CHAPTER III. 

Parallax — Measurement of Distances — Distance of the 
Moon, how determined — Distance of the Sun — Immensi- 
ty of Creation, 39 

CHAPTER IV. 

Time — Dials and Clepsydrse — Siderial Day — Transit Instru- 
ment — Geology and Astronomy, - - - - 45 

CHAPTER V. 

The Calendar — Length of the Year — The Ecliptic — Preces- 
sion of the Equinoxes — Julian Calendar — Gregorian Cal- 
endar, 53 

CHAPTER VI. 

Right Ascension and Declination — Sun Dials — Dialing — Di- 
als and Clocks, 67 

CHAPTER VII. 

Measurement of Time — Equation of Time— Longitude — 
Quadrant — Method of determining apparent Time, - - 77 



X CONTENTS. 

CHAPTER VIII. 

Page 4 

Chronology — Revolution of the Pole of the Ecliptic — Preces- 
sion of the Equinoxes — Egyptian Zodiacs, - - - 87 

CHAPTER IX. 

Signs of the Zodiac — Line of the Apsides — Change of the 
eccentricity of the Earth's Orbit, - - - 97 

CHAPTER X. 
The Seasons — Declination of the Sun — Equinoxes — Divi- 
sion of the Earth into five Zones — Sun's Path, - - 105 



PART II 



CHAPTER I. 

Meteorology — Indications of the Weather — Barometer — 
Density of the Air — Pressure of the Air — Caswell's Bar- 
ometer, ----,.--. H5 

CHAPTER II. 
Winds — Temperature of Valleys — Trade Winds— Mon- 
soons — Hurricanes— The Sirrocco — The Harmattan— The 
Simoon, --------- 125 

CHAPTER III. 
Clouds and Dew — Formation of Clouds — Various kinds of 
Clouds— Table Mountain, 137 

CHAPTER IV. 

Climate — Distribution of Heat upon the Earth's Surface — 
Different Lengths of Days — Thermometer — Isothermal 
Lines — Effect of Climate on Plants and Animals — Table 
of Temperatures, - - - " v '- - - -147 

CHAPTER V. 

Optical Phenomena — Color of the Atmosphere — Halo — Mi- 
rage — Meteoric Showers — Zodiacal Light— Aurora Bo- 
realis, - - ...-*-- 159 



CONTENTS. 



PART III. 



CHAPTER I. 

Page. 

Structure of the Earth — Probable Thickness of the Earth's 

Crust—Extent of Surface — Simple Substances — Minerals 

— Stratified Rocks — Succession of Strata, - 177 

CHAPTER II. 

Chronological Arrangement of Strata — Fossiliferous Strata 
— Tertiary System — Secondary Formations — Unstratified 
Rocks — Geological Names — Ideal Section of the Crust of 
the Earth, 187 

CHAPTER III. 

Aqueous Causes of Change — Action of Running Water — 
Sediment deposited annually by the Ganges — Excavation 
of a Lava Current — Fluviatile Formations — Peat Bogs, - 197 

CHAPTERIV. 

Springs — Artesian Wells — Calcareous Springs — Incrusta- 
tions and Petrefactions — Silicious Springs — Salt Springs — 
Subterranean Springs, - - * 207 

CHAPTER V ? 

Currents — Gulf Stream — Oceanic Currents, Chart of — Ef- 
fect of the Ocean upon Coasts — Encroachments of the 
Sea— Reculver Church— The Bore, - - - - 221 

CHAPTER VI. 

Volcanoes, Distribution of — —Line of Volcanic Vents — 
Rocky Mountains — Isolated Volcanoes, - 235 

CHAPTER VII. 

Volcanic Eruptions — Destruction of Pompeii — Eruptions of 
Vesuvius— Of Etna— Of Hecla— Of Skapta Jokul— Vol- 
canic Islands — Eruption of Jorullo, - 243 

CHAPTER VIII. 
Earthquakes, Phenomena of— Extent of Country Agitated — 



XII CONTENTS. 

Page. 
Gradual Elevation of Coasts — Temple of Jupiter Serapis 
— Elevation of Coast of Sweden — Earthquake in Cala- 
bria — In Peru, 257 

CHAPTER IX. 

Atmospheric Causes of Change — Sand Floods — Dunes- 
Chemical Influence of the Atmosphere— Disintegration of 
Granite, 271 

CHAPTER X. 

Vital Causes of Change— Coral Animalcules — Brain-stone 
Coral — Madrepores — Appearance of Living Corals, - 279 

CHAPTER XI. 

Coral Islands — Atolls — Barrier and Fringing Reefs — Whit- 
sunday Island — Bolabola — Formation of Atolls and Bar- 
rier Reefs, - 287 

CHAPTER XII. 

Organic Remains — Infusoria in Flint — Age of the Earth — 
Minerals and Fossils — Imbedding and Preservation of Or- 
ganic Bodies — Division of the Animal Kingdom, - - 295 

CHAPTER XIII. 

The Granitic Period — Basaltic Columns — FingaPs Cave — 
Graptolites— Encrinites—Trilobites— Fossil Fishes — Ferns 
— Fossil Crustaceans — The Belemnite— Flora of the Oolitic 
Period — Pterodactyle — Close of the first Epoch, - - 302 

CHAPTER XIV. 

Commencement of the second Period — Fossil Foot-steps — 
TheLabyrinthodon—Dinornis— Plesiosaurus— Ichthyosau- 
rus — Close of the second Epoch, 310 

CHAPTER XV. 

The Tertiary or third Period— Character of the Deposits — 
Fossil Remaina— The Deinotherium— Mammoth — Mas- 
todon—Elephant—Megatherium—Irish Elk— Close of the 
last Epoch, - - , - - t - - 319 



THE WORLD 



> w 

CHAPTER 1. 

Figure of the Earth. 

%i And still, as sunk the golden Orb of day, 
The seaman watched him, while he lingered here, 
With many a wish to follow, many a fear, 
And gazed, and gazed, and wondered where he went, 
So bright his path, so glorious his descent." — Rogers. 

The constant and regular succession of day and night, is the 
Jirst great phenomenon which arrests our attention, when we com- 
mence a study of nature. Day after day, we behold the sun, after 
a definite and well determined period, rising in the east, and as* 
cending the heavens; "and no sooner has the blazing orb sunk 
beneath the western horizon, than we raise our eyes to the blue 
vault, expecting and beholding the placid stars. 

Doubtless, the first impression is always, that we are at rest, and 
that the sun, and all the stars of heaven, are slowly, and forever, 
revolving around us. 

A thoughtful consideration of the phenomena which attend the 
regular return of day and night, will soon convince us that this 
conclusion is erroneous, and will point out to us the true solution 
of the grand problem. 

Let us go upon some eminence when evening draws near, and 
watch the successive changes which usher in the night. The red 
orb of the sun, shorn of his lustre, his ruddy beams scarce pene- 
trating the mists which creep over the surface of the earth, sinks 
gradually beneath the wave, or distant hills; a ruddy glow illu- 
mines the western sky, 

" Twilight's soft dews steal o'er the village green," 
slowly the light fades away, fainter and fainter, giving place to 



14 THE WORLD, 

serene night, and now the stars, which the brilliancy of day had 
eclipsed, shine forth in all their splendor, and perhaps that fairest 
one of them all, the evening star, adorns the western sky. As 
we look over the heavens, we notice here and there a group, or as 
the astronomer calls them, a constellation, with which we have 
been familiar from childhood. If we look upon the winter sky, 
we recognize Orion, with his bright belt, and the Pleiades or seven 
stars, or turning to the north, the great dipper or Charles' wain, 
being a part of the constellation "Ursa Major," or the "Great 
Bear." As the eye wanders over these familiar objects, another 
sight bursts upon the delighted vision. The full-orbed moon rises 
majestically over the eastern hills, and in the increasing light, 
the lesser stars fade away. The evening star, no longer brilliant, 
is now ready to set below the western horizon, and stars, which at 
the commencement of night, were to the east of the meridian, are 
now in the mid heaven. If we turn to the north we find a change 
there, the cluster or group called the dipper, which we will sup- 
pose, at the commencement of our observation was almost 
parallel with the horizon, as shown in this figure, has moved 




eastward, and evidently performed a part of a revolution about 
some unknown centre. If we prolong our observations we find 
this group, and all the rest of the heavens apparently revolving 
around one star, which seems not to move at all. This star is 
called the pole, or polar star, and is nearly in a line with the two 
bright stars at the end of the dipper as shown at a and b in the 
above diagram, and about five times their distance, from the nearest 
one. Meanwhile, the lunar orb, with all its beautiful diversity of 



ROTUNDITY 01' THE EARTH. 



15 



light and shade, ascends the heavens, reaches the highest point 
and declines in the west. Star after star sinks beneath the 
western hills, and new ones rise in the east. Twelve hours -pass 
away, when again the sun, rising with undiminished lustre, calls 
the busy world once more into bustle and activity. 

The phenomena thus presented, convince us that there is no 
such thing as rest, for the whole heavens seem revolving around 
us, and the first step towards an accurate knowledge of our earth 
is, that either we, or the heavenly bodies, are in ceaseless and 
regular motion. 

Suppose that before us the waters of some vast lake or ocean 
are spread out ; far as the eye can reach there seems to be a place 
where the sky is resting upon the water, called the horizon from 
a Greek word meaning "to see." As we stand, perhaps won- 
dering how far from us this horizon is, a vessel sails out the harbor 
and moves steadily from us. Now our first idea is that we are 
looking out upon a vast plain, and consequently we expect to see 
the vessel as it moves away, become fainter and fainter, until at 
last the straining eye will fail to catch the minute image. This 
appearance is shown in the engraving below. 




Instead of this, however, a new and unexpected phenomenon 
greets the eye. The vessel sails away, and soon arrives at the 
horizon, and then slowly sinks from view. First the hull disap- 



16 THE WORLD. 

pears, then the sails, and at last the flag, presenting the appearance, 
shown in this engraving. 




This then is the second step towards obtaining an accurate 
knowledge of our earth, and we learn that the surface of our 
lakes, and seas, is not an extended plain, but curved. If we were 
on a vessel at sea, we would perceive the horizon encompassing us 
like a vast circle, of which, we would be the centre. And in 
whatever direction we made an observation, we would find the 
surface of the water curving or bending from us in that direction. 
The same phenomenon is observed on land. If we ascend some 
high elevation, such as a mountain, or lofty monument, the horizon 
appears in every direction equally distant, or, in other words, a 
large circle, of which we are the centre. From this we rightly 
infer that the surface of the earth is convex, like the surface of an 
apple, or an orange. It becomes an interesting question, after 
the convexity of the earth is thus established, to determine its actual 
shape, whether it is a true sphere, or a spheroid, i.e., having the di- 
ameter through one direction longer than another, or, whether the 
curvature is of such a nature as to return into itself, for it is well 
known that there are curves, such are the parabola, and hyper- 
bola, which, however far continued, never return into themselves 
like the curve of a circle. It was therefore a bold undertaking to 
circumnavigate the globe and thus demonstrate its spherical form, 
by actually sailing around it. This was accomplished however 
by Ferdinand Magellan, or rather by the expedition which he fitted 



ROTUNDITY OF THE EARTH. 17 

out, for he himself did not live to witness the complete triumph 
of his bold attempt. Magellan was a Portuguese who had entered 
into the service of Spain. In the year 1519 he sailed for South 
America, and discovered the straits called by his name, and 
which separate the island of Terra del Fuego from the continent. 
He likewise discovered the Marian and Philippine islands, which 
he took possession of in the name of the King of Spain, and was 
killed on one of the latter group. His fleet was mostly dispersed, 
but one ship with eighteen men, returned to Spain in 1522, having 
sailed westward completely around the world. The rotundity of 
the earth, by these means, was established beyond a doubt, though 
indeed this proof was not necessary, a great variety of phenomena 
giving the same result. For example, the shadow of the earth, 
which is cast upon the moon at the time of a lunar eclipse, is 
always bounded by a curved line or circle, and it can be shown 
mathematically, that a spherical form is absolutely necessary for 
the stability of the earth. The moon, and all the planetary bodies, 
are also observed to present discs, the same as a ball suspended in 
the sky. Having learned these two things, viz : that there is a 
great and unceasing motion somewhere, and that the earth is 
round, it becomes interesting to determine its actual size, its 
diameter and circumference. Previous to determining this and 
on the supposition that our earth is the grand centre of the uni- 
verse, let us study the phenomena presented by the sun, plan- 
ets, and stars in their apparent diurnal or daily revolution around 
the earth, premising however, that to certain directions upon its 
surface the arbitrary names, North, South, East, and West, have 
been assigned. For example, we call the part towards the north 
star north, the opposite south, and facing towards the north star, 
we call the right hand east, and the left hand west. These names 
are entirely arbitrary, i. e., they do not actually represent fixed 
directions in space, but are simply relative expressions, thus, what 
is east to one observer, maybe west to another, for example, take 
the next diagram, representing the earth as round, the north pole 
being at the position N, and suppose two observers one at A, and 
the other at B, both facing towards the north. 

If questioned about some object C, B would declare it to be 



18 



THE WORLD. 



west, being at his left hand, whilst A would assert it to be east, 

c 




being at his right hand. The terms therefore, north, south, east 
and west, are only relative expressions, and not absolute direc- 
tions. It will be necessary to remember this, and we may also 
remark, the same is true of the expressions up, and down. What 
would be up to an observer at A, would be in the direction N A, 
but this would be down to an observer at B. Hence we must 
learn to consider up, as away from the earth, and down as the 
direction to its centre, and therefore not absolute directions in 
space but only relative terms. Now as the sun and the stars are 
observed after certain regular intervals to appear in the east, 
apparently move over the heavens, and set in the west, the natural 
inference is, that they are revolving in vast circles around the 
earth, which itself is the immovable centre. Below we have given 




*B 



an engraving which represents the earth as the centre, and the 



MOTION OF THE SUN. 19 

sun revolving around it in a circular orbit, and the stars still fur- 
ther beyond. Now on the supposition that this is the true system 
of the world, suppose the sun revolving in the direction A B, and 
an observer at «, facing towards the north N. He would perceiv e 
the sun appear to rise at his right hand, or in the east, and when 
the sun had travelled far enough round, say to B, to become 
visible to an observer at b, he would see it at his right hand, or in 
the east. The sun in his daily revolution, would thus track out in 
the heavens a certain line, which astronomers call a diurnal circle. 
Now suppose that some morning, just at sunrise, we observe 
a particular star, A, close to the sun, rising just before it. If the 
stars revolved around the earth in the same time as the sun, as 
they seem to do from a casual observation, it is evident that after 
any definite interval, say one month, the sun and this star would 
still be found together, but this is not the case, for after one month, 
it will be found, that this star A, which rose just before the sun, 
will now rise two hours before him, and the sun will be near the 
star C, having apparently moved backward the distance A C. If 
we should continue to observe this backward motion of the sun, 
we would find that after one year had elapsed, the sun would have 
moved completely around backward, contrary to the direction in 
which, each day he seems to move across the heavens, arriving 
again at A. Hence it would appear, that, the earth being the 
centre, the stars are revolving around it a little faster than the sun, 
but in the same direction, gaining upon the sun about 4 minutes 
a day, so that in one month the star A would gain 120 minutes or 
two hours, and rise just # so much sooner than the sun ; and thus, 
in the course of a year, the stars would make one more revolution 
than the sun. Now suppose we were to observe carefully the 
stars near and over which the sun passed in this backward motion, 
for it is evident that this path would mark out a circle in the 
heavens. Astronomers have done this, and they call this path or 
line, which has a fixed position among the stars, the Ecliptic, or 
sun's path. On the next page we represent the ecliptic, and a certain 
space on each side of it. This space includes the orbits of all the 
planets, which also partake of the same backward motion as the sun, 



THE WORLD. 



not moving on uniformly with the stars. The middle black line 




represents the ecliptic and the whole space or belt is called the 
Zodiac. The ancients divided the zodiac into twelve equal parts, 
and gave them names, indicative of the peculiar employment of 
that season of the year, when the sun happened to be in any one 
of them. For example, the sun, in the preceding diagram, is in 
the sign called Virgo, or the Virgin ; this sign was represented 
by a virgin bearing sheaves of wheat, as the sun was near these 
stars in the fall of the year, when the harvest was gathered. We 
shall refer to this again when we explain the phenomena of the 
seasons. The ecliptic was divided into twelve parts, or signs, 
because the moon makes the complete circuit in one-twelfth of 
the time the sun does, hence the twelfth of the year is called a 
moon, or a month. The time of a lunation, or interval from new 
moon to new moon, being thirty days, and twelve of these luna- 
tions happening in a year, the number of days to the year, when 
reckoned by lunar months is 360. This number of days however 
is not strictly correct, for the sun makes 365J revolutions appa- 
rently, around the earth, while moving from any particular 
star around to that star again. It would be inconvenient to sub- 
divide the ecliptic into 365 parts as this number cannot be halved, 
or quartered. So the early astronomers, adopting the lunar year, 
divided the whole circle into 360 parts, which they called degrees. 
This division, it will be understood from what we have said, was 



ANGLES. 21 

perfectly arbitrary. The circle might have been divided into just 
100, or 1000 parts, and these called degrees, but it was convenient 
to adopt for the length of a degree, a space which would represent 
the progress of the sun in one day as nearly as was possible. 
When we speak of a degree, it must be remembered that an 
absolute length is not meant, but only the 1-360 part of some 
circle. The length which belongs to a degree will vary with every 
different circle. Thus in this diagram, we have two circles with 




a common centre, and two lines drawn from that centre, including 
20 degrees of each circle. 

All circles are supposed therefore, to be divided into 360 parts, 
and the 1-360 part of any circle is called a degree. Two kinds 
' of circles are supposed to be traced on the earth, as also in the 
heavens, viz, great and small circles; this name does not arise 
from the fact that one circle is actually greater than another, the 
distinction is more marked, and is this — 




Let ABCD, &c, represent the earth, and letG C be a circle 



22 THE WORLD. 

the plane of which passes directly through the centre of the earth; 
this is a great circle. So is A E for the same reason, for if the 
globe were to be divided through these circles it would be exactly 
halved, but a circle passing through H B, or F D, is called a small 
circle, since the plane of the circle does not pass through the centre 
of the sphere on which the circle is drawn. From this definition 
it will be perceived that the circle A I E K, (the part behind the 
sphere being shown by the dotted line) is a great circle, because 
the plane of this circle passes through the centre of the sphere. 
Every great circle, has what is called a pole, that is, a point ninety 
degrees, or one quarter of a circle, distant from it in every direc- 
tion, thus — A is the pole of the circle G C, for from whatever 
point on the circle G C, the distance is measured up to A, it will 
be found 90°. For instance the arcs AG, A I, A O, A K, A C, 
are all J of their respective circles. Now suppose the circle G 
C, to represent the equator, then A will be the north pole of the 
earth, and E the south pole. Suppose now this great circle which 
we have called the equator to be actually traced around the earth 
and divided into 360 parts called degrees, marked (°), and sup- 
pose these degrees subdivided into minutes marked ('), and call 
these minutes miles, how many miles would the earth be in cir- 
cumference? Evidently sixty times 360, -or 21,600 miles. This is 
not so much as the circumference is usually stated to be ; viz, 
24,000 miles, and for this reason ; the mile at the equator, is longer 
than the English statute mile. Referring to the preceding figure, 
it will be readily perceived that if the circle H B was dividea 
into 360 parts and these again subdivided into 60 parts each, 
called miles, these miles would be much smaller than the equa- 
torial miles, indeed it would require 69J English statute miles to 
constitute 1°, or 60 equatorial, or geographical miles. Now if 
we take 69J miles for the length of a degree, it is evident the 
circumference of the earth will be 360 times this, or 25,020 miles, 
and as the diameter is a little less than J the circumference, the 
diameter is called in round numbers 8000 miles. When there- 
fore we assert that the earth is 8000 miles in diameter, we mean 
simply this, if the equator, or any great circle drawn upon the 



MEASUREMENT OF A DEGREE. 23 

earth, is divided into 360 parts, and these subdivided into sixty 
parts each, and their length ascertained, that it would take 8000 of 
them to measure the diameter of the earth. The length of a mile 
therefore, instead of determining the diameter of the earth, or its 
circumference, is itself determined by that diameter or circum- 
ference. The circle might have been divided into 1000 parts, and 
these subdivided into 100 each, this would give 10,000 minutes 
or miles for the circumference, but the mile in this case would be 
shorter. Having assumed the earth's circumference 24,000 miles, 
we next desire to know when we have passed over a mile on its 
surface. This would seem a difficult undertaking at first thought, 
for how can we determine when we have passed over a degree 
upon the earth ? A diagram will explain the manner this is 




accomplished. Let A B C D represent the earth, A C being the 
equator. A spectator at the pole B, would see the pole star directly 
overhead, but a spectator at A, on the equator, would see the pole 
star in the horizon. Hence, in travelling from the north pole to 
the equator, the elevation of the pole star changes from directly 
overhead, or in the zenith as it is called, to the horizon, or 90°, 
changing its altitude 1° for every degree traveled over the earth's 
surface, either north or south. The astronomer is furnished with 
the means of measuring the altitude of the pole star, or its 
distance above the horizon by means of the quadrant, or the 
, astronomical circle which we shall describe, together with some 
other astronomical instruments in the next chapter. We have 



24 THE WORLD. 

now learned three important facts in regard to our earth, and the 
celestial bodies, viz: The ceaseless and uniform motion, the 
rotundity of the earth, and the actual length of a degree upon its 
surface, and this is no small progress, supposing we commenced 
entirely unacquainted with the subject. Fortunately, as we pro- 
ceed to show the gradual improvement in astronomical knowledge, 
we can also give a history of the science, and briefly notice those 
eminent men, and their discoveries, whose labors have brought 
astronomical science to its present state of perfection. Supposing 
that we are ignorant of the nature of the motion perceived in the 
heavenly bodies, we will lay aside further observation for the 
present, and notice some of the instruments employed in astrono- 
mical discoveries. 






ASTRONOMICAL THEORIES. * 25 



CHAPTER II. 

Astronomical Theories. 

, '* He sat and read. A book with silver clasps, 
All gorgeous with illuminated lines 
Of gold and crimson, lay upon a frame 
Before him. ' Twas a volume of old time ; 
And in it were fine mysteries of the stars, 
Solved with a cunning wisdom." — Willis. 

The imperfect historical records of the nations of antiquity 
prevent us from determining with certainty when, and with whom, 
astronomical science had its origin. It is certain however, that it 
was cultivated at a very early age by the Egyptians, the Chal- 
deans, the Bramins of India, and the Chinese. In a fine 
climate, and fertile country, inhabited by nomadic tribes, we can 
well imagine the sublime spectacle of the heavens to have arrested 
early attention. At a later period, when the motion of the sun 
among the stars began to be noticed, and consequently the helical 
rising and setting of certain stars, i. c, their rising or setting just 
before or after the sun, became the signs of approach of certain 
seasons, the stars were grouped into constellations, and fanciful 
names given to them. Thus wef*find Hesiod alludes to the helical 
rising of Arcturus, and Thales mentions the number of days 
after the vernal equinox, when the Pleiades set just as the sun 
arose, by means of which we are now enabled to tell the age in 
which he lived, as will be explained hereafter. 

The constellations being located and named, and the sun's 
apparent path determined in the heavens, astronomers began to 
observe more carefully the motions of the sun, moon, and planets, 
among the stars, and endeavored to frame a system of the world 
which would explain all the apparently irregular motions. It was 



26 , the world! 

very early observed that the sun and moon moved around the 
earth with different velocities from the stars, and that there were 
certain bodies, five in number, which also appeared to be wan- 
dering in the heavens, these were called planets, from a Latin 
Word meaning to wander, and were named in order, according to 
their supposed distance from the earth, Mercury, Venus, Mars, 
Jupiter, and Saturn. As soon as these wandering bodies were 
closely observed, certain irregularities in their motion attracted 
attention, instead of moving uniformly in a circle in the heavens, 
like the sun, their paths were often broken, and even turned back, 
as represented by the lines below, moving from a to b direct, i. e., 



^EL 



o> 



-tC 



- o 



in the order of the signs, from b to c, retrograde, or contrary to 
their previous motion, at b and c, apparently still, or stationary for a 
short time, and from c to d moving again direct. - In addition to 
these irregular movements, two of them were observed to always 
remain in the neighborhood of the sun, viz. Mercury and Venus, 
while Mars, Jupiter, and Saturn were often seen directly opposite, 
rising when the sun was setting. Hence, in framing any theory, 
it was necessary to account for these motions. 

All the early astronomers supposed that the earth was the centre 
of the system, and that all the celestial bodies were revolving 
around it. The only system of the world which attracted much 
notice, was that of Ptolemy the great Egyptian king and philoso- 
pher, called, from him, the Ptolemaic system. This is the 
system which we would naturally adopt upon casual thought. 
Here is the earth occupying the centre, and around it the moon is 
supposed to be revolving not quite as fast as the sun, next comes 
Mercury, then Venus, the Sun, Mars, Jupiter, and Saturn, beyond 
the whole was supposed to be the grand primum mobile, a sphere 



PTOLEMAIC SYSTEM. 27 

to the surface of which the stars were all attached, and revolving 




once around the heavens in 24 hours. To account for the irregu- 
lar motions of the planets before noticed, a modification of this 




system was necessary. Thus BAC may represent the orbit of 






28 THE WORLD. 

Mercury around the earth, the planet however, instead of revolving 
in this circle, was supposed to be revolving in another smaller 
circle c a b d 9 whose centre v was carried forward as the circle A 
B C revolved around the earth, in the order of the letters, the 
planet moving in the contrary direction in the small circle c a b d 
would apparently describe the curve line d e f g h, being sta- 
tionary at/ and h, and apparently moving backward through the 
arch f g h. Now in order to make Venus and Mercury always 
accompany the sun, the centre v of the small circle, was supposed 
to be always in a right line nearly, between the earth and sun. 
Such was the Ptolemaic system, and as it appeared to explain the 
irregular motions by really uniform, or true circular motions, it was 
soon adopted as the true system of the world. In the time of 
Ptolemy astronomical instruments began to be used; for some 
time previous however, the eastern nations, in order to ascertain 
the instant of mid-summer, or mid-winter, had been in the habit 
of measuring the length of the shadow of a vertical gnomon or 
style, but Ptolemy introduced the use of graduated spheres. We 
have already observed that all circles are divided into 360 degrees, 
and these subdivided into 60 minutes each. Hence it is evident 
that by means of a graduated circle, angular distances may be 
measured in the sky. An angle, it must be remembered, is simply 
the inclination of two lines and has no reference at all to the 
length of the lines, thus S A B is the angular distance of the star 




S from the object B. To observe this angle, or inclination* we 
may use a small graduated circle thus. Let A C D be a circle 
graduated into 360°, having a moveable index turning on its 
centre, which index is furnished at each end with a sight-hole. 
First look with the index towards the object B, and observe the 



MEASUREMENT OF ANGLES. 29 

point where the index marks the circle, say at 10°, then turning 



g 




the index towards S, observe where it makes the circle, say 20°, 
the difference 10°, is the angular distance of S from B. The 
instruments of Ptolemy were constructed upon this principle 
though not so perfect, using shadows, and other contrivances, 
instead of simply observing through two vanes or sight holes. 

Ptolemy had not intended his system to be received other than 
an hypothesis, which might account for the observed motions ; he 
did not profess this to be the actual order of the world, but his 
successors, without their great master's love for truth and careful 
study, soon gave to these supposed spheres and orbs, a real exis- 
tence, and the heavens became crowded with crystalline spheres 
moving in all directions, and with all velocities, and as often as 
new motions, or irregularities in the old ones were detected, new 
circles moving at their centres round the old ones, were added, 
called epicycles, so that at last cycles and epicycles, revolved in all 
directions, bearing the planets along with them, until amid the 
crowd of spheres and crystal orbs the brain grew dizzy, and could 
not comprehend the mysterious revolutions. Amidst all this 
confusion of " Cycle and epicycle, orb on orb," a bright 
luminary arose, and with a master hand dashed aside the 
crystal spheres of the successors of Ptolemy, substituting instead, 
the simplicity of truth. This man was Nicholas Coperni- 
cus. At the time when the true system was about to be made 



30 THE WORLD. 

known, the followers of the Egyptian school were in their glory, 
Purbach, professor of Astronomy at Vienna, had reviewed the whole 
system, and by the addition of various new spheres, had succeeded 
in explaining all the observed irregularities of the planets, and 
thus silenced forever the sneers of infidels, and particularly those 
of Alphonso X. King of Castile, who had observed, "Had the 
Deity consulted me at the creation of the universe, I could have 
given him some good advice." But the hour of triumph 
was short. Error, which had sat like a cloud upon the mountain 
top, overshadowing all below, was ready to vanish before the bright 
beams of the sun of Truth. 

The obscurity which hangs over those early days, conceals the 
steps by which Copernicus arrived at the knowledge of the true 
system. It required indeed a bold mind to disregard all the 
religious dogmas of the time, and methodise a system, which as 
Tycho Brahe, himself an illustrious astronomer, observes, 
"Moved the earth from its foundation, stopped the revolution of 
the firmament, made the sun stand still, and subverted the whole 
ancient order of the universe." Such a mind however, Coper- 
nicus seems to have possessed, although his modesty prevented 
him from publishing his views, until at so late a period, that he 
only lived just long enough to see a printed copy of that book 
which was to gain him immortal honor. At this time, in the 
words of his admirable friend the Bishop of Culm, " He was 
occupied with weightier cares" — about to test the reality of that 
unknown world whose mysteries sages have endeavored but in 
vain to understand, from remotest ages. The first gleam of truth 
which burst upon the mind of Copernicus was doubtless the idea 
that the apparent revolution of the starry orbs around the earth 
from east to west once in 24 hours, was actually accomplished by 
a revolution of our earth on its axis in the same time but in the 
contrary direction. Refer to the following diagram and observe 
the simplicity of this explanation. 

Here is the earth, and around it on all sides the celestial con- 
cave. Suppose now an observer situated upon the earth should 
see a particular star A, directly overhead at sunset, and that the 
earth was revolving once on its axis in 24 hours in the direction of 



DIURNAL REVOLUTION OF THE EARTH. 31 

the letters A B, after an interval of 6 hours, the spectator would 

A 






*# 










arrive under B, and perceive the star B directly overhead while the 
star A would be just ready to sink below the horizon. After an 
interval of 18 hours more he would again arrive under A, having 
performed a complete revolution. Now as all the stars are 
observed to have a perfectly uniform motion, moving once around 
the earth in 24 hours, never changing their apparent positions 
with regard to each other, doubtless this supposition appeared to 
Copernicus the most rational, and its truth is now incontestably 
proved, and universally admitted. The great motion of the 
heavens being thus shown not to be real, but only apparent, 
Copernicus naturally endeavored to ascertain how far certain other 
motions, which the followers of Ptolemy explained by innumera- • 
ble cycles, and crystalline spheres, as if all their observed motions 
were real, might be explained by a movement of our earth 
instead of these bodies. The actual size of the sun and planets, 
as also their actual distance from the earth, not being known at 
that time, rendered this problem more difficult, and beside this, 
he was wholly unacquainted with the laws of gravitation. Hence 
it was no ordinary effort of mind to reduce the various compli- 
cated motions of the planets and the sun to one harmonious 
system. Pythagoras, the celebrated Greek philosopher who lived 
500 years before Copernicus, had already suggested the idea that 
the sun was the central body, and that the earth and planets were 
revolving about the sun at various distances. He did not attempt 



32 THE WORLD. 

however to account for the irregularities observed in the planetary 
motions. Copernicus might have easily perceived, and no doubt 
did perceive, that the motion of the sun backwards in the heavens, 
and to which we have alluded, was only apparent, and was due to 
a real motion of our earth, which may be illustrated thus : 



^****#* 




Let S represent the sun, occupying the centre of the system, 
and E the earth moving in an orbit around it. Now an observer 
on the earth at E would perceive the sun S, apparently projected 
against the heavens near the star B. If the earth was stationary, 
then after 24 hours, turning around in the direction of the arrow, 
t. e., from left to right, or west to east, (the north pole in the dia- 
gram being supposed towards the eye) the sun would again appear 
close to the star B, and the sun and stars would come to the 
meridian or mid-heaven together. Now suppose the earth to have 
moved forward in its orbit to A, and imagine the sphere of stars 
figured in the diagram to be expanded to an infinite distance, it 
will be easy to see that the sun and the star B, will no longer 
come to the meridian together, the meridian being represented by 
the black line on A, but that, on the supposition that the earth is 
turning in the direction of the arrow, the sun would come to the 
meridian, or this line, much later than the star, and would appear 
among the stars at C. To explain the motions of Mercury, and 



COPERNICAN SYSTEM. 



33 



Venus, Copernicus supposed them to be revolving around the sun, 
but in orbits within the earth's. This would explain why they 
were never seen at any considerable distance from that luminary 
and also the various irregularities observed in their motions, 
Thus : 




\ A Y 



Let S be the sun, E the earth, and V, Venus. In the situation 
represented in the diagram Venus would appear among the stars 
at A, the sun being at B. In this case, supposing the earth to 
turn on its axis in the direction of the arrow, the sun would come 
to the meridian or overhead, to an observer on its surface, before 
the planet, which consequently, setting after the. sun, would be the 
evening star. Now supposing the earth stationary in its orbit, let 
Venus move from V to W. This would cause her to describe 
the arc A C in the heavens, gradually approaching the sun, which 
is apparently at B, and then appearing on the opposite side. 
When in the position W, still supposing the earth to turn on its 
axis in the direction of the arrow, Venus would come to the 
meridian, or rise before the sun and consequently be morning 
star. During the rest of her revolution in her orbit, from W to V 
she would seem to move backwards in the heavens, or retrograde 
from C to A, and at the points C and A she would appear for a 
short time stationary. We have supposed the earth to be at rest, 



34 THE WORLD* 

4 

but it really moves in its orbit in the same direction as Venus* 
though much slower, and the phenomena are the same in kind as 
though the earth was still. The phenomena of Mercury may 
be explained in the same manner as those of Venus, but as 
Mercury is never seen at so great a distance from the sun as 
Venus, its orbit is placed between the orbit of Venus and the sun. 
The planets Mars, Jupiter, and Saturn being occasionally observed 
at midnight, or directly opposite to the sun, their orbits are 
located exterior to that of the earth, and in the order just named, 
which is according to their relative velocities. 

Such is the simple and beautiful system of the world known as 
the Copernican system. Long as time will last, the memory of 
its' successful author shall live. His fame as everlasting as the 
duration of those bright orbs which roll around the sun. Coper- 
nicus lived in an age far behind himself, and no doubt refrained 
from publishing his views to the world from fear of ecclesiastical 
censure, although indeed he ridicules this idea, and dedicates his 
book to Pope Paul III, and was induced to publish it by the persua- 
sions of Schuenberg, Cardinal of Capua, and Gisas, Bishop of 
Culm. 

In those days the Bible was not only received as the rule 
of faith, but as the oracle of nature. To assert the rotation 
of the earth on its axis, and deny the revolution of the sun around 
it, was impiety, and direct contradiction to scripture. Joshua 
commanded the sun to stand still, and therefore the sun must 
move. So it is said, "The pillars of the earth are the Lord's." 
And yet no one supposed at that time that the earth was liter- 
ally sustained on pillars. Sir Isaac Newton himself, would 
say " The sun rises," " The sun sets," and yet would mean far 
from asserting that the sun actually moved. The ignorance 
which repressed the efforts of Copernicus, at a later day crushed 
the energies of Galileo, who with his heaven-directed tube main- 
tained and demonstrated the truth of the Copernican system. 

Referring to the next diagram, it will be seen that upon the 
supposition that Venus is revolving between the sun and the earth, 
her disk would assume the phase of our moon. For example 
when at A she would appear wholly illuminated, her enlightened 



PHASES OF VENUS. 



35 



disc being turned towards the earth at E. When at B, she would 
appear half illuminated, as the enlightened hemisphere is now 
partly turned from the earth. At C, she would appear either wholly 
unilluminated or at best a slight crescent, since her enlightened 
portion is now wholly or almost wholly turned from the earth, at 
D, she would appear again half illuminated. These phases were 




not really observed in the case of Venus, although Copernicus 
predicted they would be, when we could see Venus plainer, and this 
was considered by some as an unanswerable argument against the 
truth of his theory, while others maintained that the planets shone 
by their own inherent light, and of course had no phases. Such 
was the state of science when Copernicus died, but already the 
dawn of a brighter day was advancing. The use of spectacle 
glasses was quite common, and many shops were engaged in 
their manufacture. It is related that some children of a Dutch 
optician, while playing with the spectacle -glasses one day, chanced 
to arrange two at such a distance as gave a magnified but inverted 
image of distant objects, and the optician following out the idea 
thus accidentallv presented, the telescope was first made in Hol- 
land. Galileo, at this time professor of Mathematics, at Padua, 
heard of the wonderful tube, and immediately set himself to 
work to construct one. In this he was eminently successful, and 
in his hands it gave the death blow to the opposers of the system 
of Copernicus. With the telescope, Venus was clearly ob- 
served exhibiting the phases which Copernicus had predicted. 



36 THE WORLD, 

We cannot imagine the delight which must have thrilled the 
heart of Galileo when he, for the first time since the creation of 
man, beheld the phases of the evening star. Already a cham- 
pion for the true system, he must have hailed this complete and 
unanswerable evidence, with a joy such as we cannot now 
conceive. We would have supposed that now the absurd dogma 
which asserted that the earth was the grand centre of the universe, 
and denied its diurnal revolution, would have been forever rejected-, 
but alas! error is difficult to eradicate, it takes root easily, and 
attains a most luxuriant growth, without any cultivation. 

Henceforth Galileo's life was embittered by a persecution from 
the Church. The doctrines which he maintained, and so ably 
advocated, were supposed to contradict the Bible, and at the old 
age of 70, after a life spent in the cause of science, he was the 
subject of a most humiliating spectacle. A hoary headed man, 
with trembling voice abjuring what he knew 'to be the truth, 
abjuring, cursing, and detesting as heresies those doctrines which 
he had spent the vigor of his manhood in establishing, those 
eternal and immutable truths which the Almighty had permitted 
him to be the first to establish, and with his hand on the Gospels, 
avowing his belief that the earth was the centre of the system, 
and without the diurnal motion on its axis. Oh ! that the strong 
spirit which sustained the early martyrs for religion, had supported 
this martyr of science. — But the feebleness of age was upon him, 
harrassed and tormented, worn out by long persecution, his spirit 
yielded, and never recovered from the degradation ; blind and 
infirm, he never talked or wrote more on the subject of astronomy. 
♦Here are the qualifications of these two propositions which asserted 
the stability of the sun and the motion of the earth, as qualified by 
the Theological Qualifiers : 

I. The propostion that the sun is in the centre of the world, 
and immovable from its place, is absurd, philosophically false, and 
heritical, because it is expressly contrary to the Holy Scriptures. 

II. The proposition that the earth is not the centre of the 
world, nor immovable, but that it moves, and also with a diurna 
motion, is also abiurd, philosophically false, and theologically 
considered equally erroneous in faith." 



RELIGION AND PHILOSOPHY. 37 

It hardly seems credible that such opposition could have been 
seriously entertained by grave and learned dignitaries, when the 
proofs were so abundant to the contrary. Yet at a later day, we 
find the Jesuit Fathers, P. P. Le Seur and Jacques declaring 
in the preface of their edition of Newton's Principia : 

" Newton in this third book, has assumed the hypothesis of the 
earth's motion. The author's propositions are not to be explained 
but by making the same hypothesis also. Hence we are obliged to 
proceed under a feigned character; but in other respects, we 
profess ourselves obsequious to the decrees of the Popes made 
against the motion of the earth." 

Such was the strong hold which ignorance had upon the minds 
of men, that like Sizzi, who refused to look through Galileo's 
telescope for fear he might be obliged to acknowledge the actual 
existence of Jupiter's satellites, they would not receive the truth 
when it was absolutely forced upon them. Even in the present 
enlightened state of the world, there are many who object to the 
science of Geology, because some of its teachings, they imagine, 
are contrary to the word of God. 

Religion and Philosophy can never conflict, if both are based 
upon the Truth. We may be well assured, that the rapid ad- 
vancement of science and art, will, so far from being injurious 
to the cause of Religion, tend but to illustrate, and exhibit, in clear- 
er characters, the wisdom and goodness of the Creator. Nothing 
can be more unwise, or of greater injury to the cause of Religion, 
than the foolish opposition which is sometimes made to the recent 
developments, if they may be so termed, of natural science. 
Religion points us to another sphere of action ; it opens before 
us another world; and bids us aim for higher and nobler ends than 
we strive for here. The questions, whether the Heavens are 
eternal, or our own earth a million, or six thousand years old, are 
of little moment compared with the question of the immortality 
of the soul. Science elucidates the former, Religion the latter. 
Since, then, their aim is so very different, and since we believe 
both to be based upon Truth, and therefore immutable, why 
perplex ourselves with questions which can never be answered ? 
c 



38 THE WORLD, 

To the Geologist, the proof is abundant, that the present globe 
has had a being, and been inhabited by wonderful animals and 
plants, myriads of years past. To the Astronomer, the proof is 
equally conclusive, that the Heavens are infinite, and eternal, that 
our system will, at least so far as natural causes are operating, 
continue for ever, unchanged, and unchangeable. To the 
Christian, the proof is equally strong, perhaps stronger, that the 
word of revelation is what it professes, the message of God, 
teaching what Science could never learn us, but not conflicting 
with it. 



PARALLAX. 



39 



CHAPTER III. 

Parallax. 

"The broad circumference 
Hung on his shoulders like the moon, whose orb 
Through optic glass the Tuscan artist views, 
At evening, from the top of Fesole' 
Or in Valdarno, to descry new lands, 
Rivers or mountains, in her spotty globe." — Milton. 

We have now shown that our earth is revolving around the 
sun, which is the grand central luminary, and that within its 
orbit are the orbits of Venus and Mercury, while exterior are the 
orbits of Mars, Jupiter, and Saturn. We have learned to look 
upon these bodies as orbs, or balls like our own earth, and suppose 
them to revolve like our earth upon an axis. We now desire to 
know something of their distance from us, and the actual velocity 
with which both we and they are moving. The diameter of our 
earth we have assumed at 8000 miles, or equal lengths, we can, 
from knowing this, ascertain the distance of the moon from the 
earth, and of the earth from the sun. Every one is familiar 
with the fact, that every change of position of a' spectator, 
causes an apparent change of place in the object viewed. Thus, 
if while in a certain position, we observe a particular house to be in 
the range, or same line with a distant tree, then upon changing 
our position, the house will no longer be in a line with the tree, 
but will appear to have moved in the contrary direction. This 
apparent change of place of the object, due to a real change of 
place in the observer, is called parallax, and by its means, we can 
determine the distances of the heavenly bodies. Thus, supposing 
spectators on opposite portions of the earth's surface, as at A and 
B, to view the moon or a planet, at c, the observer at A, will see 
the object c, apparently at a, while the observer at B will per- 
ceive it at the same time at b> Here is an apparent change of 



40 1HE WORLD. 

place, viz : from a to b, due to a real change in the position of 




the spectator. This change, enables us to ascertain the dis- 
tance of the object with much precision, for supposing A and 
B joined by a line, we have a triangle ABC, in which one side A 
B, is known, and all three angles — for the observers at A and B 
determine with some graduated instruments, the inclinations of 
the lines A c and B c to the line A B. We can illustrate the 
method by which the distance of an object is ascertained by means 
of graduated instruments thus : 




Suppose a spectator at B, to observe by means of a graduated 



MEASUREMENT OP DISTANCES. 41 

circle, the number of degrees subtended by a distant object, 
as a church, at A C, and let this angle be two degrees ; we have 
here a triangle ABC, and knowing its angles, and any one 
side, we can determine the other sides. Suppose we know 
the side B C, or the distance of the Church, to be 1 mile, we 
can "ascertain the height A C thus : Twice B C, or 2 miles, 
will be the diameter of a circle whose centre is the eye of the 
spectator, and whose radius, the distance of the Church. Three 
times this (nearly), or 6 miles, will be the whole circumference, 
and six miles divided by 360 will give the length of one degree, 
and twice this, since the angle A B C is 2 degrees, will give 
the height A C. Allowing 5000 feet to the mile, 6 miles would 
be 30,000 feet, and this divided by 360, gives 83J feet for the lengxh 
of one degree, consequently 2 degrees are 166§ feet, which is the 
height required. Now in any triangle whatever, we can deter- 
mine the length of all its sides, provided the length of one side is 
given and also the angles. We do not mean to be understood 
that this is the actual process employed by astronomers to deter- 
mine the distance of the moon, and other heavenly bodies, but 
simply introduce it as an explanation of the principle. 

By means of parallax, the distance from the moon to the earth 
has been ascertained to be 60 semi-diameters of the latter, and the 
distance of the earth from the sun has been determined 
to be 95,000,000 of miles. When we reflect upon this 
vast distance, the absurdity of that system which denied to 
the earth a revolution on its axis, once in 24 hours, is striking- 
ly apparent. We could not conceive of the amazing velocity 
with which the sun must move, at the immense distance 
which it is situated from the earth, if it was obliged to 
travel once around in 24 hours. It would require a rate of about 
24,000,000 miles per hour, or 400,000 miles in one minute, 
and 6,666 miles each tick of the clock. Such velocity is abso- 
lutely incredible, and this would be to save our little globe from 
turning on its axis at the rate of 1000 miles an hour, or about 17 
miles in one minute. — When the distance of any of the heavenly 
bodies becomes known, its actual diameter in miles can be easily 
ascertained. It is no more difficult to obtain the diameter of the 



42 



THE WORLD. 



moon, when her distance from the earth is known, than to deter- 
mine the height of a church steeple when we know how far it 
is from the observer. We here represent the moon and a part of 




its orbit, the earth being supposed to be at A. The distance A B 
or A C, is 240,000 miles, and the angle BAG, which is observed 
with a graduated circle, is about 30 minutes, or half a degree. 
Proceeding as in the case of the Church, twice A C is 
480,000 miles, and three times this is 1,444,000 miles which is the 
circumference of a circle whose centre is the centre of the earth, 
and whose radius, or half diameter, is the distance of the moon. 
This circumference divided by 360, gives 4000 miles for the length 
of one degree, and half this is 2000 miles the length of half a 
degree, which is the diameter of the moon. The actual diameter 
of the moon is 2140 miles, for the angle B A C is nearly 31 
minutes, or a little over half a degree. 

In precisely the same manner the diameter of the sun is 
ascertained to be 880,000 miles. Hence we learn, that if a spec- 
. tator at the sun, should look towards the earth, it would appear 
only the one hundredth the diameter which the sun appears to us, 
or not larger than a very small star. How absurd then is the idea 
that the sun revolves around the earth. — We now have a just 
conception of the solar system, and have learned to look upon the 
sun as the central body, around which the planets revolve in order, 
our earth being one of the smallest. Far beyond it, other magnifi- 
cent orbs are moving silently in the depths of space, peopled with 
myriads of intelligent beings. Very far beyond the boundary of 
our own system, we believe there are others more beautiful, and 



IMMENSITY OF CREATION. 43 

t hat every star which adorns the heavens, and upon which we turn 
such unheeding eyes, is a sun, giving light, and warmth, and hap- 
piness to its own attendant planets. Nay, more than this, we 
believe that all those countless myriads of stars which the tele- 
scope reveals, twinkling from distances so far, that if blotted 
from existence, their light would continue a thousand years, so 
long it would take to travel thence to us, are all centres of sys- 
tems, around which, worlds peopled with intelligences of the 
highest order, are revolving, and yet, we have obtained but a faint 
idea of the immensity of Creation. Where is the central throne 
from which all power emanates ? The throne of the Eternal. 
Imagination fails. Reason shrinks back abashed, but Faith, with 
more than telescopic eye, pierces to that centre, and sometimes 
catches a gleam, a faint ray of the brightness of its glory. What 
wonder that astronomy should be called the noblest science, 
since it affords scope for the highest order of intellect, and pre - 
sents truths unequalled for their grandeur and sublimity. Uncon- 
sciously we are moving on, life and death is every where around 
us, but the heavens seem unchangeable, the type of eternity. 
We are unwilling to believe that the principle within us, whatever 
it may be called, soul, spirit, or reason, which is thus capable of 
comprehending sublime truths, perishes, and becomes inanimate, 
like the dead flowers, and withered leaves. We feel an ardent 
aspiration after higher and purer knowledge, and cannot doubt 
that such longings will one day be gratified. 

These maybe called " flights of the imagination," but we would 
do well to remember, that there are things, which are as far beyond 
the imagination to conceive, and which are more strange than 
this, yet of whose reality we cannot doubt. Such is the progres- 
sion of light, and of electricity. The eye cannot follow them, nor 
the imagination, as they rush on, with a speed of 200,000 miles 
in one second ! And, quicker than this is the transmission of 
that mysterious influence, called gravitation, which acts with all- 
controlling force, through distances, utterly inconceivable to the 
human mind, causing the immense masses of the planetary orbs 
to rise and fall like bubbles on the ocean wave. Shall we then 
call all these flights of the imagination, or mere fancy, and with 



44 



THE WORLD. 



those doubting men of old, deny the reality of everything, even 
our own existence ? 




We give above a representation of the earth, as it would probably 
appear to a spectator removed to the distance of the moon. The 
same hemisphere of the moon is always turned towards the earth, 
this is caused by a revolution on its' axis in the same time that it 
revolves around the earth. Consequently,* a spectator on the 
moon, would always behold the earth as a stationary body in the 
heavens, as we should behold the sun, if the earth turned on its 
axis but once in 365 days. The apparent size of the earth, seen 
from the moon, would be a globe of about four times the diameter 
of the moon. In the imaginary view we have given, the great 
Indian Ocean is directly in front, the Pacific at the right, and 
the Atlantic at the left. The Targe inland seas are shown; also, 
Europe, Africa, Asia, and New Holland ; and around its north 
pole are fields of ice, and cloudy patches are over the whole sur_ 
face. Such a vast globe, suspended apparently in the heavens, and 
revolving on its axis with a motion easily perceptible, must be a 
magnificent spectacle, and if the moon is really inhabited, well 
worth a journey round half its surface to behold, 



45 



CHAPTER IV. 

Time. 

" The last white grain 
Fell through, and with the tremulous hand of age 
The old astrologer reversed the glass ; 
And, as the voiceless monitor went on, 
Wasting and wasting with the precious hour, 
He looked upon it with a moving lip, 
And, starting, turned his gaze upon the heavens, 
Cursing the clouds impatiently." — Willis. 

We have now determined the relative situation of our earth 
with regard to the heavenly bodies, and its size compared with 
them, and we are prepared to investigate the causes of some of 
the changes which we witness upon its surface. Previous to this, 
we will devote a few chapters to Time and the Calendar, for the 
familiar expression of a day, or an hour, or a year, seldom conveys 
to the mind the exact meaning which belongs to those terms. 
We may consider time to be a definite portion, that is, a portion 
which can be measured, of indefinite duration, or, as Young 
poetically expresses it : 

" From old Eternity's mysterious orb, 
Was Time cut off, and cast beneath the skies." 

Time was personified by the Ancients, under the figure of an 
old man with scythe and hour-glass, and a single tuft of hair on 
the forehead. The scythe was emblematic of that all-powerful 
influence which cuts down every thing as it sweeps past. Man, 
and his works, perish, and crumble before it, as the grain falls 
before the mower's scythe. Nor is the emblem unappropriate. 
The keen edge, while it sweeps through the field of ripe grain, 
suddenlv laying low the proud stalk, cuts down many a flower, 
and tender stem. The hour-glass, held in the outstretched 
hand, portrayed the passing moment, and the sand, in its cease- 
less flow, marked the ebbing of the current of life. We cannot 



46 THE WORLD. 

refrain from quoting a beautiful little poem, from " Hone's Every 
Day Book," entitled 

INSCRIPTION, 

FOR MY DAUGHTERS' HOUR-GLASS, 

Mark the golden grains that pass, 
Brightly thro' this channell'd glass, 
Measuring by their ceaseless fall, 
Heaven's most precious gift to all ! 
Busy, till its sands be done, 
See the shining current run ; 
But, th' allotted numbers shed. 
Another hour of life hath fled ! 
Its task perform'd, its travail past, 
Like mortal man, it rests at last ! — > 
Yet let some hand invert its frame, 
And all its powers return the same, 
Whilst any golden grains remain, 
'Twill work its little hour again, — 
But who shall turn the glass for man, 
When all his golden grains have ran ? 
Who. shall collect his scattered sand, 
Dispersed by Time's unsparing hand ? 
Never can one grain be found, 
Howe'er we anxious search around! 

Then, daughters since this truth is plain, 
That Time once gone, ne'er comes again, — 
Improv'd bid every moment pass — 
See how the sand rolls down your glass !" 

The forelock was also emblematical, indicating that if we 
would improve the time, we must take it by the forelock, and that 
time once passed left no hold by which it could be reclaimed. 
Such was the beautiful emblem of time devised by the ancients, 
and which we still retain. 

The diurnal revolution of the earth, or rather, as it was once 
believed, the revolution of the heavens around the earth, was 
observed at a very early day to be performed with the utmost 
regularity. The return of night, and approach of day, th6 
duration of the night and day, are the first great natural pheno- 
mena which engage attention, and we may suppose, therefore, 
that the apparent revolution of the stars around the earth was at 
a very early period, employed to determine equal intervals of 
time. Sun-dials were undoubtedly the earliest means employed 






DIALS AtfD CLEPSYDRA. 47 

to mark the passage of time, and are in common use even at the 
present day. Even* country tavern is furnished with its meridian 
or noon -line, which oftentimes is nothing more than a scratch, 
or mark in the floor, and the gnomon, or shadow-stick, is the side 
of a window or door. In our younger days, we have watched 
with far more interest, the shadow approach the humble line 
drawn on the floor of a tinker's shop, than in more mature years 
the steady passage of a star over the wires of a transit telescope. 
And we have not forgotten those days of sun-dial memory, when 
we were, unconsciously, children playing with time. We find 
allusions to the dial in the Old Testament. The dial of Ahaz, 
which was, undoubtedly, a large public edifice. Such was the 
dial constructed by Dionysius, and such the dial used by the 
Chinese, and in India. Sun-dials were liable to many objections : 
they could only be used when the sun was shining, and conse- 
quently at night, or in cloudy weather they were worthless. The 
Clepsydra, or water-clock, was therefore invented at an early date. 
It is said that they were found among the ancient Britons, at the 
time of the invasion by Julius Csesar. 

The first water-clocks were made of long cylindrical vessels, 
with a small perforation at the bottom. These being filled with 
water, marked the passage of time by the descent of the fluid 
column. Various ornamental contrivances were subsequently 
introduced, but they were all dependent upon the same principle. 

We will imagine one of the early philosophers, with his water- 
clock, starting the stream when some well known star was 
occulted, or hidden by a distant object, the tube being long enough 
to continue the stream until the next night. As the heavens 
move on, we find him watching the descent of the liquid, and at 
the approach of the succeeding evening, when the same star is 
again occulted by the same object/ he marks the level of the liquid 
in his tube, and selecting another star, for the first has gone out 
of sight, he fills the tube, and at the given signal, when the star 
passes behind the hill, or other occulting object, he permits the 
water to flow. On the succeeding evening, as this star is again 
hidden, he observes the fluid, and finds it at precisely the same 
level as before, and thus arrives at the conclusion that the stars 



48 THE WORLD, 

all revolve around the earth in the same time, or, more philo- 
sophically speaking, he learns that the earth turns uniformly on 
its axis — performing each revolution in exactly the same interval 
of time. The space thus chtained on the clepsydra, for a revo- 
lution of the heavens, we may imagine him dividing- into 
portions that will mark the subdivisions of the day. These 
divisions would not all be equal, but decrease in length as 
the height of the fluid column decreased. His instrument thus 
adjusted to measure the flight of time, we may suppose him to 
observe the exact instant of sunset, and after an interval of a 
day, again making the same observation. He would find upon 
careful observation that this interval was longer than the interval 
required for a star to revolve around the earth, by about 4 minutes, 
if his instrument would detect so small a quantity. In other words, 
he would find that the sun was apparently moving backward in 
the heavens. And now, he is, perhaps, for a moment puzzled 
which measure of time to adopt, that of the stars, or of the sun. 
Convenience points out the latter, and consequently astronomers 
regulate their time measurers to divide the solar day into 24 hours ; 
the other is called the siderial day, and is about four minutes 
shorter. 

For a long time, even after Copernicus and Galileo had estab- 
lished the fact of a rotation of the earth on its axis, there were no 
means of measuring intervals of time more correctly than by the 
water-clock. It is true, that instruments made of wheels, and 
moved by weights, were, in Galileo's time, in use, but as they 
were without any regulators, the time was too inaccurately mea- 
sured to be of any service. The discoveries which were being 
made by Tycho Brahe, and kepler, demanded some more 
accurate method of registering the time. It is related that 
Galileo, observing the swinging of a suspended lamp, in a 
Church at Pisa, and noticing that the vibrations, whether long or 
short, were performed in equal times, conceived the idea of 
adapting such a contrivance, now called a pendulum, to measure 
intervals of time. His apparatus was rude enough, and it was 
necessary to employ a boy to occasionally give the pendulum a 
slight push when it was near resting. It does not appear, at first 



SIDEftlAL DAY. 41> 

thought, that long and short vibrations will be performed in the 
same time — yet this is true, at least when the pendulum is quite 
long, and the £rcs over which it swings are of moderate lengths. 
Huygens conceived the idea of applying the pendulum to the 
clock, as a regulator, and succeeded in accomplishing this, and 
thus gave to the world an accurate measurer of time. The clock 
thus perfected, became so accurate, that it was necessary to contrive 
some more accurate means to regulate it. Hitherto, the successive 
occultations of some star, observed without the aid of a telescope, 
had been sufficient, and the time of noon, or 12 o'clock, was 
obtained by sun-dials, and other means, with sufficient accuracy, 
for the instruments hitherto employed. 

iVny occurrence, which takes place at regular intervals, may be 
adopted as a regulator of time, but the revolution of the earth on 
its axis is by far the most accurate. For certain reasons, which 
will be given presently, the sun is apparently subject to such 
irregularities, that the solar days, or exact interval, from the time 
the sun is on the meridian, until his return to it again at the 
successive revolution, are of unequal lengths. In other words, the 
solar day is variable. Now the real revolution of the earth on its 
axis, is the time in which any given meridian, or situation on the 
earth, moves from a particular star, back to that star again. Thus : 
A. 




~* 



Let A, B, C, D, be the earth, its north pole N, being towards 
us, and suppose it revolving in the order of the letters. Let N D 
be the meridian, or north and south line passing through some 
particular spot, Greenwich, for example, shown at E, and let the 
star S, be upon the meridian, that is, if this line was extended to 
the heavens, or, more properly, a plane passing through this 



50 



THE WORLD. 



line, suppose the star to be upon it. As the earth turns on its axis, 
the star is left behind, and after a complete revolution, the meridian 
again arrives to it, this interval is called a sideriuPday, or day as 
determined by the stars, and to ascertain this day, or its length, 
we must have some means of determining with the utmost 
exactness when the star is on the meridian. This is accom- 
plished by means of the transit instrument, invented by Huygens, 
and shown in the engraving below. 




The ordinary transit instrument consists of a telescope, A B, of 
any convenient length, fixed firmly at right angles to a conical 
hollow axis, E F, the extremities of this axis are truly turned, 
and rest in two angular bearings which are called Y's, since they 
are not unlike this letter, the instrument can be lifted out of these 
bearings, and reversed, so that the ends E and F may change 
places. The end of the axis F, is furnished with a small graduated 
circle C, for the purpose of reading the elevation, or altitude of 
the body observed, and at D, is a small lamp, the light of which 
shining into the hollow arm E, is reflected by a reflector inside 
the tube, down to the eye. The object of this illumination is 
to make a system of fine lines, usually raw silk, or spiders-web, 
visible at night, at the same time with the star. In looking into 
the transit telescope, five of these lines are usually seen, shown in 
the engraving. A B is, by means we cannot now describe, located 



TRANSIT INSTRUMENT. 



51 



the telescope A B, will move in the meridian, i. e., it will, if 
as exactly in the meridian as possible. It will be seen that when 
the axis of the* transit telescope, E F, is placed due east and west, 
and also made perfectly horizontal by means of the spirit level H, 




directed to the heavens, mark the exact situation of the meridian, 
at the time, of the particular place where the instrument is 
located. We are thus furnished with the means of determining, 
with the greatest exactness, the precise time of a siderial revolu- 
tion of the earth, and as the apparent time of noon, or twelve 
o'clock, is precisely the instant when the sun's centre is on the 
meridian, we are also enabled to determine, with considerable 
precision, the local time, or clock time at the place. 

The transit instrument and the astronomical clock, are the two 
chief instruments of the observatory, and by their means, the 
positions of celestial objects can be ascertained with the utmost 
nicety. It would be out of place for us to describe more minutely 
these invaluable aids to the astronomer, and we pass to consider 
in the next chapter, the "Calendar," or the division of the year 
into months, weeks, and days, and at the same time we shall give 
an historical sketch of its gradual progress to the present state of 
perfection. 

It is a difficult thing to comprehend fully, or even partially, the 
relative dimensions, situation, and movement of our globe. We 
are so accustomed to look around us and behold the solid founda- 
tions of the earth, to see plains and oceans, extending as far as the 
eye can reach, and man is so small, when compared with the 



52 THE WORLD. 

immensity of creation around him, that we are wont to look upon 
the hills as everlasting ; and the ground whereon we tread, and 
in the utmost confidence build houses, and proud works of art, as 
unchangeable* We are so accustomed to behold the grand luminary 
which gives light and warmth to the world, and cheers myriads 
with its bright rays, rising and marking out the length of a day ; 
we are so accustomed to plan ahead, and to contrive for years yet 
to come, as though there was no possibility of a change ; we 
are so accustomed to behold the fair orb of night, as she illumines 
a quiet and sleeping earth, and so wont to gaze upon the ever- 
twinkling and bright stars, that we long ago have ceased to think 
of our earth as a minute orb, smaller by far than many of those 
upon which we turn such careless eyes now. We rarely, if ever, 
imagine that its present surface was once the bed of a vast ocean ; 
that its present crust has been caused to heave and swell like a 
sheet spread out upon the waves, uplifted by internal fires, until 
the strained surface has cracked open, and the flames, and molten 
rock found egress. Careless from a thousand causes, we deem 
ourselves, like the conceited wise men of old, as the only impor- 
tant beings of the universe, and our habitation, as eternal, and 
unchangeable. It is the peculiar province of Astronomy and 
Geology, to free the mind from such superstitions, and to elevate 
and ennoble it by loftier contemplations. The younger Herschel, 
has truly remarked, " Geology, in the magnitude and sublimity 
of the objects of which it treats, undoubtedly ranks next to 
Astronomy in the scale of the sciences." 

We have, in the present volume, associated the two, as was 
necessary in giving such a sketch of the earth as was planned, 
and shall strive to interest as well as instruct the reader. — Of 
one thing we are most certainly convinced, and that is, there 
is not a more interesting subject, to which we may devote our 
attention. 



THE CALENDAR. 53 



CHAPTER V, 

The Calendar, 

" Change of days 
To us is sensible ; and each revolve 
Of the recording sun conducts us on 
Further in life, and nearer to our goal." — Kirk White. 

The revolution of the earth on its axis, being adopted as the 
standard of measure, it was natural that the number of days to 
the year should be a subject of early investigation. We have 
already alluded to the helical rising of the stars, and it is apparent 
that upon ascertaining the distance of the sun from any particular 
star, and after a certain interval, determining when 'his distance 
from the same star, is the same as before, the early astronomers 
could determine the length of the year, or time occupied by the 
sun in his apparent revolution around the earth. As it was diffi- 
cult to observe any stars at the same time with the sun, its place 
in the heavens, or position in the ecliptic, was determined by 
measuring its distance from Venus, and then the distance of 
Venus from some known star. Or, we may imagine the time 
of sunset to be carefully observed, and afterwards the time of 
setting of some particular star, then, upon making due allowance 
for the time elapsed, the sun's position among the stars could be 
ascertained. The rising and setting of certain stars, or constel- 
lations, was early adopted as the precursor of the return of certain 
seasons of the year. We find continual allusions to this among 
the early poets, and even in the Book of Job, we have, "Canst 
thou bind the sweet influence of the Pleiades, ox loose the bands 
of Orion? The Pleiades were also called Vergillae, i. e., daughters 
of the spring. The Egyptians watched in like manner the rising 
of the dog star, which gave notice of the approaching season of 
inundation by the Nile. The length of the year was soon 



54 THE WORLD. 

ascertained to be about 365 days ; and as the moon, apparently, 
made near 12 revolutions around the earth in that time the year 
was subdivided into 12 months, which, in reference to the phases 
of the moon, were again subdivided into weeks, of seven days 
each. — The time occupied by the sun in the departure from any 
particular meridian, until its return to that meridian again, is 
called a Solar day, and a similar revolution, a star being the 
object, is called a Siderial day. We have already shown that 
the Solar day was longer than the Siderial day, on account of the 
apparent backward motion of the sun among the stars ; but it is 
obvious, that the Siderial day, is the true measure of the time of 
revolution of the earth on its axis. Now if the earth made an 
exact number of revolutions on its axis, during the time in which 
it moves from a particular part of the heavens, back to that par- 
ticular position again, it is evident we would have an exact 
number of siderial days to a year. 

It is found, however, that the siderial year does not consist of 
an exact number of days, but contains, also, a fractional part of a 
day. When a long interval of time elapses between different 
observations, so that the earth makes a great number of revolu- 
tions around the sun, the length of the year maybe very correctly 
ascertained. Thus — On the 1-st day of April, 1669, at Oh. 3m. 
47s., mean solar time, (which we shall explain presently,) 
Picard observed the distance of the sun from the star Procyon, 
measured on a parallel of latitude, to be 98° 59' 36". In 1745, 
which was 76 years after, La Caille observed the sun, to deter- 
mine exactly the time when his difference of longitude should be 
the same from the star, as in Picard's observation. Now the day 
of the month in which La Caille observed, had been reckoned on 
from Picard's time, just as if the year had consisted of exactly 
365 days, except every leap year, when a day had been added, 
for a reason that will appear presently. It was not until April 2d, 
at llh. 10m. 45s., mean solar time, that the difference of 
longitude was the same as when Picard observed. Now here it 
was obvious that the earth had in reality, made just exactly 76 
revolutions. The number of days however, was as follows, viz : 
58 years, of 365 days each, and 18 leap years, of 366 days each, 



LENGTH OF THE YEAR. 55 

and Id. llh. 6m. 58s. more, or in all, 27759d. llh. 6m. 53s., 
which being divided by 76, gives 365d. 6h. 8m. 47s. for the length 
of the Siderial year. More recent and exact observations give 
365d. 6h. 9 m. lis. 

There are various kinds of years. First, the Siderial year, or 
the time which it takes the earth to perform exactly one revolution 
around the sun. This year it is not expedient to use, for the 
seasons being dependant on the position of the earth with regard 
to the sun, it is more convenient to have for the length of a 
year, the time from the commencement of spring to the com- 
mencement of spring again, and this is a period which, for a 
reason we will soon explain, is shorter than a siderial year. This 
year is called a Tropical or Equinoctial year. Again, inasmuch as 
this year does not consist of an exact number of days, and as it 
would be excessively inconvenient to have a year begin at any 
other time except the commencement of a day, we have the Civil 
year, which consists of exactly 365 days, and even* fourth year, 
of 366. — We have already given the length of the Siderial year, 
which is the time of a true revolution of the earth in its orbit, 
but the length of the equinoctial year, or year from beginning 
of spring, to spring again, is shorter than this. It is obvious 
that the equinoctial year is the one which most intimately con- 
cerns us, all agricultural, and other operations, being entirely 
dependant upon the seasons. 

When we explain, in the next chapter, the cause of the seasons, 
we shall show why this year, must be shorter than the Siderial 
year. Meantime we may suppose one of the early philosophers 
detecting it in this manner. The path of the sun in the heavens 
being ascertained, it was soon observed that it was inclined at a 
certain angle, with the apparent diurnal paths of the stars. Thus, 
if we observe a certain star to-night, (mid-summer,) which rises 
due east, and watch its diurnal path, or the line which it traces 
in its apparent motion over the heavens, we will find it a part of 
a circle, whose centre is the pole of the heavens, near which the 
pole star is situated, -and the star will set due west : at a certain 
point midway between east and west, it will reach its highest 
altitude, after which it will begin to set, this highest altitude is 



56 THE WORLD. 

when it is in the meridian, or mid-heaven, and the meridian of a 
place, is a plane, or direction, which passes through the spectator, 
and the north and south point. If we observe another star which 
rises 10° south of east, we will find it arriving to the meridian 
something more than 10° lower down 'than the other star, 
according to our latitude. If we were at the equator, it would be 
just 10°. This star would set 10° south of west, and so of any 
stars whatever, they would all apparently describe diurnal circles, 
or parts of such circles, all having the pole of the heavens for 
their grand centre. Now at the time of the summer solstice, or 
mid-summer, 21st of June, the sun rises directly east, and sets 
due west, describing apparently a diurnal circle in the heavens, 
after a few days, however, he will rise a little south of east, and 
set a little south of west, and in a few days more he will rise still 
farther south of east, and set so much south of west, until at the 
time of the winter solstice, or mid-winter, he will, in our northern 
latitude, rise very far towards the south, and come to the meridian 
very low down, and set at as great a distance south of the west 
point, as he arose south of the east. Now, if the backward motion 
of the sun in the heavens, had been performed in a diurnal circle, 
he would rise later and later each day, but always just at the 
same distance from the east. Hence we infer, that this 
backward motion of the sun, is not in a diurnal circle but inclined 
to it. This is the case, the ecliptic, or sun-s apparent path, 
instead of corresponding with the equator, or with any particular 
diurnal circle parallel to the equator, cuts them all at a certain 
angle, which angle is called the inclination of the ecliptic. In 
order to make this part of our subject clear, we must have 
reference to a diagram. 

Let P P', be the poles of the celestial vault or concave, having 
the earth A, within it, its poles being in the line P P'. As the 
earth turns around on its axis, Jet its equator reach the heavens, 
marking E E' as the celestial equator. Through a point B, at the 
distance of 23j° from the equator, suppose a line B S, which 
also passes through the centre of the earth, to reach the sky at 
S. As the earth .turns around, this line, B S, will mark out a circle 
in the heavens, C S, called, for a reason which will soon be given, 



THE ECLIPTIC. 



67 



the tropic of Cancer. A similar line D S, which passes through 



















1 7? 


qi — — 




y^' 




^\ \ 





Jp' 



the centre of the earth, and a point 23J° south of the equator, 
will trace out the circle C S', called the tropic of Capricorn. The 
circle P E' P' E, will represent a meridian, or a great circle which 
passes through the poles and the centre of the earth. Let SS', 
be a great circle, (of course seen edgewise in the diagram) this 
will represent the ecliptic which is inclined 23J° to the equator 
E E'. When the sun is at S in the ecliptic, his apparent diurnal 
path in the heavens, as the earth turns around, will be the circle C 
S ; and to a spectator at B, the sun would be directly vertical, or 
overhead, at noon. If we suppose a little circle marked on the 
earth, corresponding with C S, we can readily perceive, that, as 
the sun is fixed, while the earth turns around, all those places 
upon the earth which lie in this circle, will have the suri vertical 
at noon. But a spectator at A, nearer the north pole of the earth, 
would have his Zenith, or highest point of the heavens, as at Z, 
hence the sun would come to the meridian below the Zenith. 
This is the case at all places north of the tropic of Cancer, or 
south of the tropic of Capricorn. Suppose now the sun to have 
moved in his orbit from S to O, he would then appear to rise at 
the same time with the star O, and describe the diurnal circle F 
G in the heavens, parallel to the equator, arriving at the meridian 



58 



THE WORLD, 



considerably lower than in the first case. The dotted line POP' 
will here represent the meridian, which, it must be, remembered, 
is not a fixed direction in space, but simply a plane, extending 
from the earth to the heavens, and passing through the spectator, 
wherever he may be, and the poles of the earth. When the sun, 
after moving through one fourth of his orbit, arrives at the point 
where the equator and ecliptic cross each other, and which is 
called the 'equinoctial point, the days and nights are equal all over 
the world, and the sun is vertical at noon, at the equator. His 
apparent diurnal circle will now be the equator E E'. The sun, 
still moving on in its orbit, finally arrives at S' its greatest southern 
limit, describing the diurnal circle S' C at the time of the winter 
solstice ; after which it again moves northward, rising higher, 
and higher, each day, until after a tropical year, it arrives at the 
point S, where we commenced. Now if the points S and S', 
were fixed points in the heavens, the length of a tropical, or equi- 
noctial year, would be the same as the length of a siderial year, 
for the equinoctial points are fixed with regard to the tropical 
points. It is, for many reasons, more convenient to reckon this 
year from equinox to equinox, and hence this is generally termed 
the equinoctial year. 



* a * 

^-"^S^'^Ai 




Let A B C D, represent the sun's path, inclined 23° 28' to the 
equator E D F B, and suppose B, the position of the vernal equi- 



PRECESSION OF THE EQUINOXES. 



59 



nox, and let the apparent positions of the ecliptic and the equator, 
or rather portions of them, be represented by the dotted lines, and 
suppose some star S, to lie directly in the equinoctial point, or 
node, as seen from the earth at H. Suppose the sun, commencing 
from the point B, or S, to move around in the direction B A D C, 
it is evident, that if the crossing point still corresponded with the 
star S, or remained unchanged, the sun would arrive at B, or S, 
after an interval equal to a siderial year. But this is not the case, 
the plane of the equator E D F B, is not fixed, but while the sun 
is performing his journey, it moves slowly backward on the ecliptic 
contrary to the apparent yearly motion of the sun in the heavens, 
so that, in about the time of a year, the crossing points are at N 
and O, and in the heavens the position of the vernal equinox will 
appear to have shifted, contrary to the order of the signs, from S 
to T ; hence, as the sun arrives at T before it can come to S, the 
equinoctial year is shorter than the siderial year. This shifting of 
the nodes is called the Precession of the Equinoxes, because the 
equinox seems to go forward to meet the sun, and thus precedes 
the complete revolution of the sun in the ecliptic. Now this 



f£ 










.M* 


-#-; 


-%•'/ 

&L 


.* 


\ 






#Jl 




\ 


Hk- 


*#.. 


*... 


--a*... 






change of place, in the position of the equinox, we infer very 



60 THE WORLD, 

readily, must be caused by a motion of our earth, for it will be 
noticed, that the inclination of the ecliptic to the equator remains 
unchanged. 

Let ABC, represent the ecliptic, and D B E, the celestial 
equator, intersecting each other in two opposite points, one of 
which is shown at B. Let P P' be the poles of the earth, 90° 
distant from the equator F V G, in every direction, and let the 
star S, in+the direction P' P, be the pole of the heavens, every 
where 90° distant from the celestial equator, D B E, let the point 
T, be the pole of the ecliptic ABC. We must be careful and 
not consider the lines F G, H I, marked on the earth as equator 
and ecliptic, to be fixed, because this would cause the nodes, or 
equinoctial points, to revolve, apparently, once in a day, through 
the heavens, but we may suppose them hoops or bands, sta- 
tionary, while the earth turns around in them. For a moment 
suppose the diurnal revolution of the earth to be stopped, and let 
the position of the intersections of the planes of the celestial ecliptic 
and equator, meet on the earth at V, and let the poles, of the 
ecliptic H V I thus marked on the earth, be O and R, a spectator 
at the centre of the earth, would locate the equinoctial point among 
the stars at B. If, now, the earth should be turned a little, not on 
its diurnal or equatorial axis P P', but on its ecliptical axis O R, 
in the direction of the letters C B A, the equinox would appear to 
shift in the heavens to the star X, and the pole of the heavens S, 
would appear to have moved partly around the pole of the ecliptic 
S, and be at Z. This is the fact, whilst the earth is moving around 
the sun, and all the time turning daily on its equatorial axis, it is 
making a slow backward revolution around its ecliptical axis, and 
as the stars are fixed, the equinoctial point continually retrogrades 
along the ecliptic, thus causing the pole of the heavens continually 
to shift its place, revolving in a circle whose radius is T S, which 
is the angular inclination of the axis P P' to the axis O R, or of 
the plane of the ecliptic, to the plane of the equator. The early 
astronomers, located the places of the equinoxes in the heavens, 
and gave the name Aries to the constellation where the vernal, 
or spring equinox, was located, and the name Libra to the con- 
stellation where the autumnal equinox was located. Since that 



PRECESSION OF THE EQUINOXES. 61 

time, the equinoctial point has retrograded 30°, or one sign, the 
whole circle, 360°, being divided into 12 signs of 30° each ; 
consequently, the vernal equinox is now in what was then the 
last constellation, Pisces, for the stars have not changed places, 
only the intersecting point. Astronomers, however, have agreed 
to call the point where the vernal equinox is situated, the first point 
of Aries, forever, whatever may be the constellation where this 
point is located, hence the sign Aries, is now in the constellation 
Pisces, the sign Pisces, in the constellation Aquarius, &c. The 
annual amount of precession is small, being but 50.1" in a year, 
hence the time occupied to make a complete revolution, will be 
25,863 years. However, small as it is, it is quite palpable in the 
course of a century, and has been of signal aid in Chronology as 
we shall show in our chapter upon that subject. As the place of 
equinox goes forward each year, to meet the sun, 50.1 seconds of 
space, it is evident the tropical or equinoctial year will be as much 
shorter than the siderial year, as it takes the sun to describe this 
small space, which is 20m 20s, nearly, hence the length of the 
equinoctial year is 365d, 5h, 48m, 51.6s, and this is the year which 
most intimately concerns us. In ancient times, the days of the 
summer and winter solstice were determined by means of the 
shadow of a gnomon, or upright post, as the sun rose higher and 
higher each day, at noon, the shadow became shorter and shorter, 
until, having reached its limit, it began to lengthen, this was the 
day of the summer solstice. The day of the winter solstice, was 
the time of the longest shadow. When, we look back, and think 
of the ancient philosophers, with their shadow-sticks, and rude 
dials, and see them trying, with these rough means, to measure 
the distances of the heavenly bodies, and the size of the earth, we 
may wonder that they ever approximated as near as they did. In 
no Science has the advancement of general learning and civiliza- 
tion been more apparent, than in Astronomy. Tables of the posi- 
tions of the sun, moon and planets, in the heavens,are now given for 
many years to come, with such accuracy, that the unassisted eye 
cannot detect even their greatest errors, and in some cases, the 
positions are given with more accuracy than even could be obtained 
from observation itself. 

D 



62 THE WOKLft. 

The tropical, or equinoctial, or mean solar year, for these dif- 
ferent names all mean the same, is, as we have just shown, about 
365£ days long. Now if this year was to begin upon the first day 
of January,- at Oh, Om, Os, the next year must begin January 1st, 
at 5h, 48m, 51.6s, or about a quarter of a day later. This would 
be excessively inconvenient, hence it was determined to have the 
civil year consist of 365 days exactly, and this, for a long period, 
was the case, but the consequences, after awhile, became very 
apparent. The vernal equinox, which once was at the commence- 
ment of the spring months, gradually began to go back, until the 
calendar was involved in great confusion. This was especially 
the case with the Roman Calendar, in which the year was reckoned 
12 revolutions of the moon, or 354 days, and Julius Caesar, with 
the aid of Sosigenes, an astronomer of Alexandria, attempted a 
reformation. The beginning of the year had formerly been placed 
in March, by Romulus, in honor of his patron, Mars. Caesar 
determined to commence the year the 1st of January, at the time 
of the winter solstice. This seems the most natural time, for 
now, the sun, having reached his greatest southern declination f 
begins to return, bringing back the spring and summer. Coesar 
chose, likewise, to have, for the first year of the new calendar, a 
year when a new moon happened near the time of the winter 
solstice. This occurred in the second year of his dictatorship, and 
the 707th from the founding of Rome, when there was a new 
moon on the 6th of January. This, accordingly, was made the 
beginning of a new year, and in order to make the year commence 
at this period, it was necessary to keep the old year dragging on 
90 days, or to consist of 444 days. All these days were unprovided 
with solemnities, hence the year preceding the commencement 
of Caesar's calendar is called the yea* of confusion. To prevent 
the recurrence of error, which was what he had most in view, and 
keep the civil and astronomical years together, he determined to 
add, each fourth year, a day to the calendar, because the solar year 
being, as was then supposed, 365J days long, this J, would, in four 
years, amount to a day, and could then be added. It was true, 
the second year would begin 6 hours too soon, the third would 
begin 12 hours too soon, and the fourth 18 hours too soon, but the 



JULIAN CALENDAR. 63 

commencement of the fifth would correspond with the fifth astro- 
nomical year. In the month of February, the lustrations, and 
other piaculums to the infernal deities, ceased on the 23d day, 
and the worship of the celestial deities commenced on the 24th. 
Caesar chose, therefore, to insert this intercalary day between 
the 23d and 24th days of February. The Romans did not number 
their days of the month as we do now, i. e. 1st, 2d, 3d, &c, but 
they called the first day the Calends, from which our word calendar 
is derived, thus the 1st day of March was called the Calends of 
March, the 28th day of February was called the pridie Calendar 
Martias, the day before the calends of March, the 27th was called 
the third day of the Calends of March, and the 24th was the sextus, 
or sixth day, of the Calends of March, and as Caesar's intercalary 
day was added just after this day, it was called bissextile, or double 
sixth day, and the year in which it was added, received, and still 
bears the name, bissextile. Many years after, when Christianity 
became the religion of the Roman Empire, Dionysius Exiguus, a 
French Monk, after much research, came to the conclusion that 
the 25th day of December, of the 45th year of Caesar's era, was 
the time of the nativity, commonly called Christmas, and therefore 
the 1st of January, of the 46th year of Caesar, was adopted as the 
1st of the Christian era. As the first year of Caesar was a bissextile, 
and as even* fourth year after the 45th, was a bissextile, conse- 
quently the fourth year of the Christian era was a bissextile, and 
as every fourth year is the one in which the intercalary- day is 
added, we can always determine when this year occurs, by simply 
dividing the year of the Christian era by 4, if there be no remain- 
der, the year is a bissextile, or leap year, but if a remainder, then 
that remainder shows how many years it is from the last bissextile. 
The name leap year is given, because the civil reckoning, which 
had fallen behind the astronomical, leaps ahead and overtakes it. 
The correction introduced into the calendar by Caesar, would 
have been sufficient to always keep the astronomical and civil 
reckoning together, if the fraction of a day over 365 had been just 
6 hours, or J ; instead of this, however, it is but 5h, 48m, 51.6s, 
and the difference is 11m, 8.4s, which, in 4 years, amounts to 
44m, 33.6s, by which amount, the fifth civil year begins later than 



64 THi' WORLD. 

the astronomical year. In 1582 this difference had accumulated, 
until it amounted to over 11 days, of course the equinoxes, and sol- 
stices, no longer happened on those days which had been appointed 
to them, and the celebrations of the Church festivals, were conse- 
quently* much deranged. The Council of Nice, which sat A. D. 
325, had decreed that the great festival of Easter, should be 
celebrated in conformity with the Jewish Passover, which was 
regulated by the full moon following the vernal equinox. Now 
the decree did not say that this festival, upon which all the others 
depend, should be on the first Sunday after the full moon following 
the vernal equinox, but on the Sunday following the full moon, 
on or after the 21 si of March, this being the day, at that time, of 
the vernal equinox. Pope Gregory XIII., who occupied the 
pontificate in 1582, determined to rectify this error, wmich was 
thus made known, not from any series of observations for that 
specific purpose, as at the present day, but by the accumulated 
error becoming so great as to introduce confusion. At this time 
the vernal equinox really occurred, accordingto the civil reckoning j 
on the 11th of March, ten days earlier than the time decreed by 
the Nicene Council. To remedy this defect, Gregory directed 
that the day following the 4th of October, 1582, should be reckoned 
the 15th, instead of the 5th, thus restoring the vernal equinox to 
its former position, by omitting altogether ten days. To prevent 
the accumulation, he directed the intercalary day to be omitted 
on every centurial year ; this would have answered every purpose 
if the difference, which had caused the error, had amounted to a 
day in 100 years, but it did not, for it was but a little more than | of 
a day, hence omitting the intercalary day every 100th, or centurial 
year, omitted J of a day too much, which, in the course of 400 
years, amounts to 1 day. It was, therefore, further provided, that 
although the intercalary day was ordinarily omitted each centurial 
/ year, it was to be retained every 400th year, thus the centurial 
years 1600, 2000, and 2400, are bissextile ; but the years 1500, 
1700, 1800, 1900, 2100, 2200, &c>, are common years. This 
correction is sufficiently accurate for all purposes, the slight re- 
maining error will only amount to a day after an interval of 144 
centuries. The time of the vernal equinox now is, and always 



GREGORIAN CALENDAR. 65 

will be, the 21st of March. The correction introduced into the 
calendar by Gregory, was not adopted by the English, until the 
year 1752. At this time the difference between the Julian and 
Gregorian calendars was 11 days ; it would have been 12 days, 
but the latter had omitted the intercalary day in the year 1700, as 
we have already stated. It was, therefore, enacted by Parliament, 
that 11 days should be left out of the month of September of the 
current year, by calling the day following the 2d of the month the 
14th, instead of the 3d. The Greek Church have never adopted 
this Romish or Latin correction, and consequently, the Russians 
are now 12 days behind us in their reckoning, and the Christmas 
festival, which happens with us December 25th, occurs with them 
January* 6th, or Epiphany day, according to our reckoning, and 
which is sometimes, even now, called M Old Christmas day." 
The Julian and Gregorian calendars are designated by the terms 
" Old Style," and " New Style." Thus, by successive improve- 
ments, which have been almost forced upon the world, the calendar 
has been perfected, until it answers all the purposes of civilized 
life. 

" Time," says Young, "is the stufTthat life is made of," and 
we do well, therefore, not to waste such a precious possession. 
We remember the inscription on the dial in the Temple, at Lon- 
don : " Begone about your business," a wholesome admonition 
to the loiterer, and the no less appropriate device, once stamped 
on the old Continental coppers, a dial with the motto, " Mind 
your business." There is enough to do, and time enough to do 
all that ought to be done. " There is a time for all things," says 
Solomon, let us then, be careful and do all things in the proper 
time. The French Chancellor d' x^-guesseau, employed all his 
time. Observing that Madame d 5 Aguesseau always delayed ten 
or twelve minutes before she came down to dinner, he composed 
a work entirely in this time, in order not to loose an instant ; the 
result was, at the end of fifteen years, a book in three large 
volumes quarto, which went through several editions. 

No man, we venture to say, ever accomplished more, and to 
the better satisfaction of all interested, than Benjamin Franklin, 
another economiser of time. One of his greatest discoveries was 



66 THE WORLD. 

made in France, and that was, Sun-light was cheaper than lamp- 
light, and better, too. A severe reprimand, from a man of his 
standing, and industry, upon the customs of the French court, 
spending the night in mirth and revelry, and sleeping all the day. 

It is said there is a moral in everything, to the moralizing mind. 
Since, then, " Time once gone, ne'er returns," let us make the 
best use of it ; not sad, or serious, merely, but sober and reasona- 
ble — ready to labor in the hours of labor, and to rest in the hours 
of rest. We shall not, then, look back on misspent moments, 
with that feeling so aptly expressed in the German : " Ach wie 
nichtig, ach wiefluchtig /" Ah, how vain, ah, how fleeting ! 

The flight of Time, which is silently, but surely and uniformly, 
bearing us from scenes, loved, perhaps, too well, cannot be too 
accurately marked. The correction of the calendar, by Julius 
Caesar, has done more to perpetuate his name than the victories 
he won for Rome, and the name of Gregory XIII. has more of 
meaning in it, than that of a mere Saint, in the Romish calendar. 
There is something pleasing, and yet mournful, in thus minutely 
contemplating the passage of the year, and we would do well to 
imitate the good old custom which our forefathers followed, and 
on the first day of the New Year, 'make the first entry in our new 
account books : 

£ a u Deo. 



SIDERIAL TIME. 67 

CHAPTER VL 

Dials and Dialing, 

*'This shadow on the Dial's face, 
That steals from day to day 
With slow, unseen, unceasing pace, 
Moments, and months, and years away, 
Right onward, with resistless power, 
Its stroke shall darken every hour, 
Till Nature's race be run, 
And Time's last shadow shall eclipse the sun." 

J. Montgomery, 

In the preceding chapter, we have made frequent use of the 
word day, and have throughout meant what is called a mean Solar 
day. We have already shown that the Siderial day is the time of 
an exact revolution of the earth on its axis. This day is shorter 
than the Solar day, by about 4 minutes. We have also alluded 
to the apparent motion of the sun in the heavens, showing that if 
to-day he came to the meridian at the same time with any particular 
star, to-morrow the star would come to the meridian before the 
sun, which had apparently changed its place in the heavens. Let 
us consider to what the difference between Solar and Siderial time 
is really owing, and see how much the Siderial day should be 

A, 




shorter than the Solar, to do which we will have recourse to a 

diagram 



68 THE WORLD. 

Let A B C D, represent the earth's annual orbit, showing- the 
earth in four different positions, and let a be the situation of some 
particular meridian, that of Greenwich, for example. Now, on 
the supposition that the earth does not rotate on its axis at all, 
suppose it moving in its orbit, in the order of the letters ; it is not 
difficult to see that the effect will be the same, as though the earth, 
remaining at rest in its orbit, had turned once on its axis during 
the year, but in a contrary direction to its present diurnal mo- 
tion. Thus, while at A, the sun would be on the meridian 
a, but at B, one fourth of a year after, the sun would set in the 
east, and at C, half a year afterwards, it would be midnight at the 
same meridian, a. At D the sun would just begin to rise in the 
west, and finally at A would come to the meridian again. It will 
now be understood, that although the earth does turn on its axis, 
during its yearly circuit, yet this day as really occurs as if the 
earth had not the diurnal revolution, hence the number of rotations, 
measured by the sun's coming to the meridian, will be less than 
the number as announced by a star, by one day, and therefore the 
Siderial day must be shorter than a Solar day, by the proportional 
part of a revolution, which is thus divided up among, and added 
to the 365 Solar days of the year. Upon the supposition that the 
mean Solar day is just 24 hours in length, the Siderial day will be, 
the one-three hundred and sixty-fifth and one-fcurth, of 24 hours, 
shorter, i. e.. 3m, 56s, very nearly, and a star, in consequence, 
will come to the meridian 3m, 56s, sooner than the sun, each 
day, or will gain so much on the sun daily. 

We have more than once intimated that the time elapsed be- 
tween a star's leaving the meridian, to its return to it again, viz : 
23h, 56m, 4.01s, is the precise measure of a rotation of the earth, 
and for this reason astronomers prefer to regulate their time keepers 
to show what is called Siderial time. Now, suppose to-day to be 
the 14th of April, which is near the time of vernal equinox, the 
precise point where the ecliptic intersects the equator, we will 
imagine to be shown by a bright star. By means of his transit 
instrument, the astronomer ascertains exactly when this star is on 
his meridian, and just then sets his clock going, the hands showing 
at the time Oh, 0m, 0s, and at the same time the town-clock, we 



RIGHT ASCENSION AND DECLINATION, 69 

will suppose, or some other time-measurer, such as a watch, or 
ordinary clock, is set going, showing, also, at that instant, Oh, Om, 
Os. Now the astronomer's clock is, like the other time-keepers, 
divided into 24 hours, only he reckons straight forward from 1 to 
24 hours, while in the ordinary time -piece, the hours are numbered 
twice in a day, from 1 to 12. We ought to say, however, that the 
astronomer begins his day at noon the 14th of April, while the 
civil day, April 14th, began at midnight, 12 hours before, but 
both clocks now show Oh, Om, Os. The astronomer's clock has a 
pendulum a trifle shorter than the common clock, which makes it 
oscillate somewhat faster, so that the gain, on the ordinary clock, 
may be about 3m, 56s, in a day. After an interval of 24 hours, 
by his clock, the astronomer again looks into the transit telescope 
and sees the supposed star, or equinoctial point, which is always 
called the first point of Aries, just on his meridian, that is, if his 
clock is truly adjusted, but it is not yet a day, or 24 hours, by the 
civil time, but lacks 3m, 56s. The next day the clocks will be still 
farther apart, and in about 15 days there will be 1 hour's difference, 
the siderial clock showing lh, when the ordinary clock shows 
12h, or noon ; the latter shows the time when the sun is on the 
meridian, or very nearly so, but the former indicates that the first 
point of Aries, or the equinoctial point, crossed the meridian an 
hour before. Now the great convenience to the astronomer is this : 
As the whole heavens appear to revolve around the earth in a 
siderial day, he imagines a circle traced out in the heavens, which 
corresponds to our equator, and, commencing at the vernal equi- 
noctial point, or first point of Aries, he divides this, celestial equator, 
into 24 equal portions, or hours, and these he subdivides into 60 
minutes, and each minute into 60 seconds, and he calls the distance 
of any body from this first point of Aries, measured on the celestial 
equator, just as we measure longitude on a globe, or map, by 
ascertaining how far east or west the place is from Greenwich, 
measured on the terrestrial equator ; this he calls the Right As- 
cension of that body, designated by the initials R. A., and the 
distance of the body north or south of the equator, he calls De- 
clination, north or south, designated thus: N. D., or S. D., 
corresponding with our geographical terms, north and south 
p* 



70 THE WORLD* 

latitude. The only difference between longitude as reckoned on 
the earth, and right ascension as measured in the heavens, is, 
the former is reckoned east or west from any arbitrary point, 
Greenwich, or Washington, for example, but the latter is reckoned 
eastward, or in the order of the signs, completely around, and 
always from the first point of Aries, which is a determined point 
in the sky, being the position of the vernal equinox, and which 
turns around, apparently, with the whole celestial concave, in its 
diurnal revolution. 

When a new comet appears, and is announced as having a R. 
A. of 6h, and 10m, and N. D, of 2° 15', the astronomer places his 
transit telescope, or other similar instrument, so as to point 2° 15' 
north of the imaginary celestial equator, for he knows just how 
high above the horizon this is situated, and when his clock points 
out 6h and 10m, he looks into the telescope and sees the newly 
discovered object. Thus the precise position occupied by any 
star, or planet, in the heavens, can be mapped down, using right 
ascensions and declinations in the same manner as terrestrial 
longitudes and latitudes. We should like to say a great deal more 
on this subject, but the nature of our work forbids. 

Our ordinary clocks and watches, are adjusted to keep mean 
solar time.. It would, at first, be supposed, that the interval from 
noon to noon, although longer than a Siderial day, would, never- 
theless, be an equal period, so that if a clock was adjusted to show 
24 hours during the interval of the sun's leaving the meridian at 
any particular season of the year, to his return to it the next day, 
it would always indicate an interval of 24h, for any similar revolu- 
tion. This is not the case, and we think we can show, very 
plainly, why it is not. The instant when the sun is actually on 
the meridian, is called the time of apparent noon, or 12 o'clock 
apparent time, although, a clock regulated to keep what is called 
mean time, or mean solar time, may then show but llh, 45m. 
The difference between apparent time and mean solar time, is 
called the equation of time, i. e. the correction which must be 
applied in order to determine true time, from the time indicated 
by the sun. It is evident that Sun-Dials will indicate apparent 
time, and we will, therefore, devote the remainder of this chapter 



S7W- DIALS. 71 

to a description of the principles of dialing, and then proceed to 
illustrate the causes, which make the discrepancy observed between 
the times indicated by a clock supposed to run with an uniform 
motion, and a good sun-dial. We do this the more willingly, 
for we intend our book to be of some advantage to the reader, and 
we trust that after its attentive perusal, he will feel sufficiently 
interested to either erect a good dial, or a meridian mark, in order 
to determine his local time with something more of accuracy 
than suffices for the ordinary wants of life. We mean by local 
time, the correct solar time for the place, in distinction from 
Greenwich time, or Siderial time. Chronometers, which are 
accurate, but portable, time-keepers, are often set to Greenwich 
time, i. e. they are adjusted so as to 6how, wherever they are 
carried, the actual time then indicated by the clock at Greenwich, 
the difference between this and the time indicated by the clock at 
any other place, or the local time will give, by simple inspection, 
the difference of longitude. 




Let P A B C, be the earth, and E the position of a spectator 
upon it, and let F G be the horizon, or a horizontal circle, and let 
C H A be the plane of a great circle parallel to the small circle F 
(r. and let P B be the axis of the earth inclined to the diameter 



72 



THE WORLD. 



C A of the great circle C H A, according to the latitude of the 
spectator E. Now as the earth turns once on its axis in 24 hours, 
it is evident that the several meridians P, P I, P II, P III, &c., 
will come successively under the sun at exact intervals of 1 hour, 
if they are all 15° apart, for 24 multiplied into 15 gives 360, the 
whole number of degrees to the circle. Suppose, for a moment, 
that instead of the earth turning up on its axis, once in 24 hours, 
that the sun moves around the earth in this time, the effect will 
be the same If the sphere of the earth was transparent, but its 
axis P D B opaque, then P D would, as the sun passed around, 
cast a shadow in the directions DA, DI, DII, Dili, &c, when 
the sun was in the opposite direction, and the progress of this 
shadow would mark the hour, according to the meridian in which 
it should fall. It will be observed, that the intervals A-I, I-II, II- 
III, are not equal intervals, but vary, because the circle C H A, 
cuts the meridians obliquely. Now the sun is so far distant, that 
if the observer at E should locate a horizontal plane, which, of 
course, would be parallel to the large plane C H A, and describe 
on it a small circle, and then divide this circle in proportion as 
the meridians divide the large circle C H A, and should, likewise, 
erect from its centre a gnomon, or shadow stick, inclined so as to 
point to the north star, or in other words, to be parallel to P D, the 
progress of this shadow would mark the hour. We have here, 




then, the principle of the horizontal Sun-dial, and all that is 
necessary to construct one, is, to graduate it proportionally accord- 
ing to the latitude. This can easily be done by calculation, which, 
however, would involve more of mathematical skill than we shall 
suppose the reader to possess ; we will, therefore, show how it 
may be done experimentally, and thus any one, with the least 
ingenuity, can construct a horizontal dial. Referring back 



DIALING. 73 

to the figure, page 71, it will not be difficult to perceive that if the 
circle C H A, had been the equator, then all the angles of the 
hour lines D A, D I, D II, &c, would have been measured by 
equal arcs, each 15°. The same would be true of any small 
circle, IK, parallel to the equator, the meridians, 15° apart, would 
divide it into 24 equal parts. Now, if on a globe, we should 
divide any parallel of latitude, such as I K, before alluded to, into 
24 equal parts, and then pass a plane, a sheet of paper for example, 
through each of the'se divisions and the centre of the globe, then, 
wherever this plane intersected the plane of any other circle, C 
H A for example, it would mark out the directions of the hour 
lines D A, D I, D II, D III, &c. Take, now, a flat board, on 
which a sheet of paper is fastened, and describe a circle whose 
centre is O, as in the diagram below, and let O B be a metallic 




rod, inclined to the line A C, drawn on the paper to represent a 
meridian line, at an angle equal to the latitude of the place, let 
D E be a small circle, so fixed on O B, that its plane is everywhere 
perpenc^cular to it, or in other words, so that the distance from 
the point B to the circumference of the circle, may be the same 
throughout. Lcet this smaller circle be graduated into 24 equal 
parts, and subdivided into halves, and quarters, and if desired, 
still smaller spaces. Take, now, a fine thread, or a straight edge, 
and carry it from B through each division of the little circle, 
successively, down to the plane of the paper below, taking care, if 
a thread is used, not to crook it against the edge of the little circle, 
but simply passing it straight down. Through the points F, G, H, 



74 THE WORLD. 

I, &c, thus indicated on the paper, and the centre of the circle A, 
draw the hour-lines A F, A G, A H, &c, extending, however, 
only to the circumference of the circle, and we have a dial ready 
for use, after adding the figures. Of course the little circle must 
be so adjusted that when the line is passed by some one of its 
graduations, it will reach the horizontal plane at a point in the 
meridian line A C. Instead of a wire for the gnomon, we may 
use an inclined plane, so that our dial will now be not unlike this 







figure. In order to use it, we must next determine the north and 
south line, or a meridian line, and place the line on our dial which 
marks XII, to correspond therewith. This may be ascertained 
by means of a surveyor's compass, provided the variation of the 
needle from true north is known ; or, at the time of the solstices, 
mid-summer or mid-winter, when the sun's declination is 
changing very slowly, a number of circles may be traced upon a 
horizontal plane, having a common centre, over which centre a 
plumb-line must be suspended, having two or three knots tied in 
it. Upon marking where the shadow of these knots falls, suc- 
cessively, on the circles, in the forenoon and afternoon, and then 
bisecting the space so measured on each circle, and drawing a 
line through the centre and these points of bisection, a pretty 
exact meridian line may be laid down. The use of several circles, 
is simply to ensure greater accuracy in the result. We will now 
suppose the dial constructed, and located in a window facing to 
the south. We may here observe, that there will be no use in 
graduating the dial all the way round, as that portion only can be 
used over which the shadow passes during the day, say from 5 
o'clock to 5 o'clock, on each side, viz : from V, on the western 
side, through VI, VII, VIII, IX, X, XI, to XII, and from XII, to 
V, on the eastern side. When the sun rises before 6 o'clock, say 



DIALS AND CLOCKS. 75 

at 5 o'clock, it will then be shown at V, by the shadow on the 
western side of the dial, and the shadow cannot be observed on the 
dial to advantage much later than 5 o'clock, Suppose, then, the 
dial located, and that when the shadow indicates XII, or apparent 
noon, a well regulated clock is started, the hands of which also 
indicate XII, and this on the 24th day of December, for, as we 
shall soon see, this is one of the four days in the year when the 
clock and dial agree, then, although for a few days, the clock and 
dial will appear to indicate the hour of noon together, it will soon 
be observed, that the clock begins to gain on the dial, and after 
an interval of one month, the clock will show 12h, 13m, when the 
dial indicates noon, or 12 o'clock apparent time. This difference 
will go on increasing, until February 10th, or 11th, when the 
clock will appear to lose time, and by the 25th of March will be 
only 6m. faster than the dial, and on the loth day of April they 
will again correspond. The clock, after this, will continue, appa- 
rently, to lose time until about May 15th, at which time it will 
only indicate llh, 56m, when the dial shows noon ; after this, its 
rate seems to increase, and on the 16th day of June they again 
come together. The clock now continues to gain on the dial until 
July 25th, when it is about 6m, 4s, faster, after which, its rate 
apparently decreases, until at August 31, they again coincide. 
On the 2d of November, the clock shows lib, 43m, 46s* when 
the dial says it is noon ; this is the greatest difference of all, being 
16m, 14s, after this they begin to come together, and on. December 
24th, again correspond. Now, can it be that the sun's motion in 
the heavens, or rather the earth's motion, is thus irregular ? We 
might, at first, suspect our clocks, and watches, but the utmost 
pains have been bestowed on these, and when their rates of going 
have been ascertained, by means of the stars, and a transit instru- 
ment, as already described, they are found to go perfectly uniform, 
or very nearly so. Hence we are forced to admit, that the dis- 
crepancy between the dial and the clock, is to be sought for in the 
movements of the earth, and we shall fully show, in our next 
chapter, what these are. 

Thus far we hope we have succeeded in explaining the phe- 
nomena of the heavens due to the movements of the earth, nnd 



76 THE WORLD. 

we have, we trust, been sufficiently clear. If, in some parts, we 
have been tediously minute, the more intelligent reader will 
remember we are writing for those who may be less expert. 
Certainly every one must feel interested in understanding the 
causes of some of the most striking phenomena which are con- 
tinually occurring. The varying lengths of days, the annual 
round of seasons, the constant return of day and night, the tides, 
the winds, and the clouds, all these force themselves upon 
observation, and demand some attention. To the consideration 
and elucidation of these great phenomena, the wisest men of all 
ages have devoted their lives, and simple and clear as the illustra- 
tion of these great natural causes may now appear, they have cost 
an amount of human labor and severe study, which we might in 
vain attempt to estimate. We feel not the less satisfaction, that 
we can look beyond the occurrences of the day and understand 
the causes which are concealed from careless eyes. The earth 
is no less beautiful, and beloved by us, because we can look above 
and see worlds, which we know to be a thousand times larger, 
and on which, we sometimes fancy, myriads of intelligent beings 
are existing, all pursuing the same great ends as we. After all, 
we are well satisfied with the study of our own planet, and find 
enough upon its surface, or below it, to fill us with admiration and 
wonder, and see enough in it of beauty, whether glowing in the 
warm sun-light, or reposing in the quiet rays of the moon. 



ORBIT OF THE EARTH, 



CHAPTER VII. 

Measurement of Time. 

• - The Pilots now their rules of art apply, 
The mystic needle's devious aim to try; 
Along the arch the gradual index slide*, 
While Phrebus down the veitic circle glides, 
Now, seen on ocean's utmost verge to swim, 
He sweeps it vibrant with his nether limb. 
Their sage experience thus explores the height 
And polar distance of the source of light." 

Falconer, 

Hitherto we have spoken of the earth's orbit as circular, such 
being its apparent projection upon the celestial sphere, but this is 
not the actual case, it is elliptical. This is ascertained by the 
change in the apparent diameter of the sun, viewed from the 
earth at different seasons. If the orbit of the earth was a great 
circle, having the sun in its centre, it is obvious that the angle 
subtended by his disk would at all times be the same, for his dis- 
tance from the earth would always be the same. On the contrary, 
the diameter is observed to increase from the summer solstice to 
the winter solstice, then to again decrease. It is a proposition 
established in optics, that the apparent diameter of an object, 
varies inversely as the distance from the spectator, when the angle 
is small, hence by observing with great accuracy, the gpparent 
diameter of the sun, at different periods of the year, and actually 
projecting or calculating the orbit of the earth, it is found to be an 
ellipse, or oval, as represented in the following diagram. The* 
sun being situated, not in its centre, but nearer one side, in what 
is called one of the foci of the ellipse. The foci of the ellipse S 
and C, are so situated on the major, or longer axis, of the ellipse, 
that the sum of the length of any two lines drawn from the foci to 
the same point in the circumference of the ellipse is constant. 
Thus the sum of the lengths C E and S E, are equal to the sum of 



78 



THE WORLD. 



the lengths C O and S O, or C D, and S D, and all are equal to the 

o 




length of the major axis A B. By placing two pins, one at each 
focus of the ellipse, and tying a thread around them of such length 
as will give the requisite major axis, a true ellipse may be described, 
by stretching the string and moving a pencil around in the angle. 
In the preceding diagram, we may suppose S E C, S O C, S D 
C, to be three positions of the string, the pencil being placed in 
the angles E, O, and D. Such is the peculiar property of the 
ellipse, and in such an orbit the earth is moving around the sun. 
Let S be the position of the sun, and A the position of the earth, 
at the time when nearest the sun, and when, consequently, the 
sun's diameter appears the largest. This point in the orbit, is 
called the perihelion point, from two Greek words, which mean 
near or about the sun. The point B is called the aphelion point, 
or point away from the sun ; when the earth is in this position, 
the sun's diameter appears the smallest. The line B A, is called 
the line of the apsides, i. e. the line without deviation, or change 
in length, for we shall show, presently, that whatever changes the 
earth's orbit may undergo, this line will remain* unaltered. In 
the preceding chapter, we observed that the sun's motion was 
not uniform in the heavens, or did not correspond with the indi- 
cations of a well regulated clock. It will not be difficult to under- 
stand, that since it is the attraction of the sun which causes the 
motion of the earth, it will, while approaching the sun, have its 
motion continually accelerated, or quickened, until it sweeps 
around the perihelion point A, with its greatest velocity, its motion 



DIALS AM) CLOCKS. 79 

will then decrease, -and it will move slowest when it passes the 
aphelion point B. The earth is at the point A, on the 31st of 
December, and at the point B, six months after, or July 1st, If 
the inequality between the time indicated by the dial and that by 
the clock was caused wholly by this change in the velocity of the 
sun, then the dial and clock should agree exactly when the earth 
was in these two positions, for the earth occupies just 6 months 
in moving from A to B, and 6 month? in returning from B to A, 
just what it would if its orbit was a circle, and in which case the 
dial and clock would agree. But by actual observation, the dial 
and clock are not together twice in the year, but four times, and 
then not when the earth is at A and B, December 31, and July 
1st, but on December 24th, April 15th, June 16th, and August 
31st, as we have already intimated. We must look, therefore, 
to another source, which, united with {he one we have just con- 
sidered, will fully explain all the i phenomena, and we 
find it in the inclination of the sun's apparent path to the equator. 
As the earth turns on its axis, we may suppose a rod which ex- 
tends from the centre of the earlh, and through its equator to the 
sky, tracing out a line, or circle, in the heavens, which is called 
the celestial equator. This circle is, as we have already shown, 
divided into 24 parts, called hours, each hour comprehending 15 , 
and all these spacer iy equal. If ih arly path 
in the heavens had corresponded with tho equator, or had been in 
the same plane, then all the difference between the dial and clock 
would have been simply what was due to his moving sometimes 
apparently faster than at others, in consequence of the earth's 
elliptical" orbit, but this is not the case, the plane of the ecliptic, or 
sun's path, is inclined to the plane of the equator. Now, on the 
supposition that the orbit is circular, let M sec what effect this 
would have upon the sun-dial. In the next diagram, the circle 
0, 1, 2, 3, 4, 5, &c, which are hour divisions, represents the 
equator, and I, II, III, IV, V, VI, &c, which are also hour di- 
visions, the ecliptic. Clock time is measured on the former, for 
this is the circle, or others parallel to it, in which the stars, and 
other heavenly bodies, seem to move on account of the diurnal 
rotation of the earth. Dial time is measured on the ecliptic, and 



80 THE WORLD. 

we have just shown that the dial was graduated, or marked, with 




unequal divisions on this very account. The little cross strokes 
at II, IV, VI, &c, indicate the position of the sun each month 
from the vernal equinox, P is the north pole of the heavens, and 
P 1, P 2, P 3, &c. are meridians cutting the ecliptic I, II, &c. above 
the equator ; is the place of vernal equinox, VI the position 
of the summer solstice, XII the place of the autumnal equinox, 
and XVIII of the winter solstice. On the 2d day of May, which is 
about midway between the vernal equinox and the summer sol- 
stice, the sun would be at the point III, but if it had moved over 
three equal divisions of the equator, it would be at 3, and now if 
a meridian be passed through 3, as at P 3, it will intersect the 
ecliptic beyond III, i. c. on the side towards IV. Now III being 
the place of the sun, if we suppose a meridian passing through P 
and III, it will intersect the equator on that side of 3 towards 2, i. e. 
the sun would come to the meridian by the dial before it would by 
the clock, for the dial will show 12 o'clock, when the meridian, 
which passes through III, is in the mid-heavens, at any place, 
but the clock will show 12, when the meridian, which passes 
through 3, is in the mid-heavens, and this would be after the dial. 
On the supposition that the earth's orbit is circular, the dial and 
clock would now, when the sun is at III (May 2d), be farthest 
apart, after this they would come together and correspond at VI, 
and 6, the time of the summer solstice, after this the clock would 



LONGITUDE. 81 

be faster than the dial till the time of the autumnal equinox, then 
slower till the winter solstice, and again faster till the vernal equi- 
nox. The earth's orbit is not a circle, but if the line of apsides A 
B, see figure on page 78 corresponded with the line VI-XVIII, in 
direction, then the clock and dial would agree at the time of winter 
and summer solstice, i. e. December 23, and June 21st, but it 
does not, for we have seen that the earth is in perigee December 
31st, and in apogee July 1st, hence, in forming a table to show the 
equation of time, i. e. the correction that must be applied to the 
dial, or apparent solar time, in order to obtain true solar, or what 
is called mean time, which is the time in ordinary use, we must 
compound the two inequalities, for sometimes when the dial 
would be fastest, on account of the unequal motion of the sun in 
his apparent orbit, it would be slowest from the effect of the incli- 
nation of the plane of the ecliptic, to the plane of the equator, 
thus, April 15th, the dial will be slower than the clock, from the 
inequality of the sun's motion, about 7m, 23s, and at the same 
time it will be faster, from the obliquity of the ecliptic, about the 
same amount, hence they are really together on that day. The 
tables of the equation of time, are thus constructed. We have 
now explained, somewhat at length, the method of obtaining true 
time, from the time indicated by the sun, for it is of the utmost 
importance to the astronomer, and the navigator, to be able, on 
all occasions, to determine the local time. 

It must be evident, that inasmuch as the earth is round, the sun 
will appear, as the earth turns on its axis, to rise and come to the 
meridian successively at every point upon its surface. If, therefore, 
some particular spot, Greenwich for example, is chosen, whose 
meridian shall be the one from which the time, or longitude, is 
reckoned, then if we know what time it is at that meridian, when 
the sun happens to be on the meridian at another place, we can, 
at once, by taking the difference between the times, viz : noon at 
that place, and, perhaps 4 o'clock P. M., at Greenwich, determine 
that it is 4h, west of the meridian of Greenwich, or, allowing 15° 
to the hour, 60° west. The meridian of Greenwich, where the 
Royal Observatory is located, is generally acknowledged as the 
first meridian, and longitude is reckoned east or west from it. In 



82 



THE WORLD. 



the United States, the meridian of Washington is very often used. 
Navigators are accustomed to carry with them Chronometers, 
or very accurate time-keepers, which are set to Greenwich time, 
and give, at any moment, by simple inspection, the precise time 
which is then indicated by the clock at Greenwich. On a clear 
day, the true time on ship-board, or the exact instant of apparent 
noon, is ascertained by means of the quadrant, figured below. 
This is an arc of a circle, embracing something more than one- 
eighth of the whole circle, but it is graduated into 90°, for the 
degrees are only half the length they would be, if the angles were 
measured without being twice reflected. 




A is called the index glass ; it is a plane quicksilvered glass 
reflector, placed, by means of adjusting screws, truly perpendicular 
to the plane of the quadrant, and attached to the brass index arm 
A B, this index turns on a pin directly under A. C is called the 



Ql"ADRA>"I. 



83 



horizon glass, and is also adjusted to be perpendicular to the plane 
of the quadrant, the upper part of this glass is unsilvered, so that 
the eye, applied at the eye-hole D, may look through it. The 
index A B, carries, what is called a vernier, which subdivides 
the graduations on the limb of the instrument E F, into smaller 
portions, usually into minutes. When the index is set to 0, and 
the eye applied at D, the observer will perceive, if he looks through 
the horizon glass at the horizon, that the portion of the horizon 
glass which, being silvered, would prevent his looking through, 
will, nevertheless, show the horizon in it almost as plain as if it 
was transparent, it being reflected on to it by the index glass A, 
and then again reflected to the eye, thus, Fig. 1, A is the index 





(Fig. 1). (Fig. 2). 

glass, its back being towards the eye, and C the horizon glass, and 
D E the horizon, seen almost as plain in the silvered portion of C, 
as through the transparent part. If the glasses are all rightly ad- 
justed, then, even if the position of the quadrant be altered, as in 
Fig. 2, the line of the horizon will still be unbroken, but move the 
index ever so little towards 1°, or 2°, and immediately the reflected 
image of the horizon will sink down, as shown in this diagram, 




a space equal to that moved over by the index, and if a star shoulct 
happen to be just so many degrees, or parts of a degree, above 



84 THE WORLD. 

the horizon, as the index had been moved, and as shown at a, it 




would appear in the quadrant, as in the figure preceding,brought 
to the line of the horizon. Now just before noon, on ship-board, 
the sailor sets the index of his quadrant to about the altitude of 
the sun, and defending the eye by a set of dark glasses, shown at 
G, page 82 he looks through the eye -hole D, and the unsilvered 
portion of the horizon glass, and sees a distinct image of the sun, 
almost touching the horizon, thus : 




It is true, he cannot see the horizon in the silvered portion of the 
horizon glass, but he can bring the image close to the line where the 
silvering is removed from the glass* and then by inclining his qua- 
drant a little, as in figure 2, page 83, he can make the sun, appa- 
rently, describe the dotted arc c d, just touching the horizon. We 
will suppose he is looking just before noon, i. e. before the sun 
comes to the meridian, or reaches his highest altitude in the 
heavens, and that an assistant stands near, ready to note the time 
when this highest point is reached. As he looks through his 
quadrant, the image of the sun, which a moment before described 
the arc c d, and appeared to touch the horizon in its course, will 
seem to rise a little, he therefore moves the index, and brings it 
clown again, all the time sweeping backward and forwards ; if it 
rises a little more, he again brings it down, very Sbon he perceives 






APPARENT TIME. 85 

it to be changing its position scarcely at all, and gives notice to the 
person with the watch, or chronometer, to be ready; in a moment, 
instead of rising, as before, it begins to dip below the horizon, 
and he calls out, and the time is accurately noted. This is the 
exact instant of 12 o'clock, apparent time, or the instant when the 
sun, having reached its highest point, begins to decline. Now 
the chronometer, with which he has been observing, does not say 
12 o'clock, but perhaps, 3h. 5m. 10s. in the afternoon. We will 
suppose the observation to be made on the 27th day of August. 
On this day, as will appear from a table showing the equation of 
time, a clock adjusted to keep true solar time, should show 12h, 
lm. 10s. at apparent noon, and this is the time which the clock 
would show at Greenwich, at apparent noon there upon this day; 
but when it is apparent noon at the place where we have just 
supposed an observation made, the Greenwich clock shows 3h. 
5m. 10s., the difference is 3h. 4m., which, allowing 15° for each 
hour, indicates that the observation is made in a place 46° west 
of Greenwich. It is west, because the sun comes to the meridian 
later than at Greenwich. Now if the latitude was known by ob- 
serving the altitude of the polar star, then, by referring to a chart, 
the position, either on ocean or land, where the observation was 
made, could be indicated; for all charts, or globes, which represent 
the earth's surface, have lines drawn upon them, through the 
poles, called meridians, showing every degree east or west of 
Greenwich, and also every degree north or south of the equator. 
We will close this somewhat tedious chapter, with an allusion 
to a circumstance which has sometimes puzzled the uninitiated, 
viz : two ships may meet at sea and vary in their reckoning a day 
or two. Suppose a traveler, leaving New York on a certain day, 
to travel continually east, until after a certain time, one year, 
or perhaps twenty, he arrives at the place from which he started; 
and farther, suppose he has kept an accurate note of the number 
of days which has intervened. For every 15° he has traveled 
east, the sun has risen one hour earlier to him than to those 
left behind. This gain, by the time he has traveled 360°, amounts 
to a whole day, and when he arrives home he finds his reckoning 
one day in advance of his neighbors, or in other words, he has 



86 THE WORLD. 

i 

seen the sun rise once more than they have. The year to him 
has consisted of 366 days, but to his neighbors of only 365. Now, 
what is not at all an improbable case, we will suppose him 
arriving home on a leap year, on the 28th day of February, and 
which he calls Sunday, the 29th, but those who have remained at 
home call it Saturday. The next day, February 29th, is, according 
to them, Sunday ; here is another Sunday in February, but there 
have already been four others, viz : the 1st, the 8th, the 15th, and 
the 22d, making six Sundays in this shortest month. It is said 
that this case has actually occurred ; that a ship left New York on 
Sunday, February 1st, and sailing eastward continually, arrived 
home, according to her log-book, on Sunday, the last day in the 
same month, but really on Saturday, according to the reckoning 
at home. The next day, being the intercalary day, made the 
28th, and 29th both, Sundays to the voyagers ; thus giving six 
Sundays to the month. If, on the contrary, a voyage had been 
made westward, one day would have been lost in the reckoning, 
as the sun would rise one hour later for each 15°, and if two 
travelers should leave the same place, say on Tuesday, and each, 
after passing completely around the globe, the one east, and the 
other west, should again meet at the same place, there would be 
a difference of two days in their account, the one calling the day 
Monday and the other Wednesday, when, in reality, it would be 
Tuesday. 



CHRONOLOGY. 87 



CHAPTER VII, 

Chronology. 

" Brightly ye burn on heaven's brow ; 
Ye shot a ray as bright as now, 
When mirrored on the unruffled wave 
That whelmed earth's millions to one grave." 

E. P. Mason. 

We have more than once mentioned the importance of the 
movements of the heavenly bodies, in determining certain chro- 
nological questions, and will now give some farther illustrations 
of this subject. The precession of the equinoxes, and the occur- 
rence of solar and lunar eclipses, are the two astronomical 
events which have been of most essential service. We have, 
in the preceding pages, illustrated the precession of the equinoxes, 
showing that the places of vernal and autumnal equinox, or the 
points where the ecliptic intersects the plane of the equator, moved 
westward at the rate of 50 J seconds of arc in one year. The 
phenomena of solar and lunar eclipses, we have not explained, 
nor does it fall within the limits we have prescribed to our little 
volume, to embrace them. We shall, therefore, only refer at 
present, to the service which chronology has received from the 
knowledge of the retrogradatioii of the nodes of the earth's orbit, 
on the ecliptic. As already shown, the path of the ecliptic in the 
heavens, is divided into 12 equal parts, of 30° each, called signs, 
and these signs formerly gave the names to the constellations, or 
groups of stars near which they were located, when the ecliptic 
was thus first divided or portioned out. That point in the ecliptic 
where the vernal equinox is located, was then, and has been 
always, designated as the first point of Aries, but as this equi- 
noctial point changes its position, moving contrary to the order of 
the signs in the ecliptic, at the rate of 50.2 seconds a year, the first 
point of the sign Aries no longer corresponds with that group of 



88 THE WORLD. 

stars to which it formerly gave a name, for the shifting of the 
equinox cannot carry forward the stars with it. The vernal equi- 
noctial point is now situated in the constellation Pisces, having 
altered its position about 30° since the constellations were grouped 
and named in their present order. As we know the annual 
amount of the precession, we can determine how long ago the 
present zodiac was formed, viz : 

50.2" : 1 year : : 30° (=108,000"): 2155.6 years, 
that is, about 300 years before the Christian era, when the most 
celebrated astronomical school of antiquity, flourished under the 
auspices of the Ptolemies, and the labors of the astronomers of 
that school, the most celebrated of whom was Hipparchus, who 
formed a catalogue of the stars, were recorded in the Almagest of 
Ptolemy, and constituted the chief knowledge, upon this subject, 
until the times of Kepler, Tycho Brahe and Copernicus. The 
conclusions which we may come to, from ancient astronomical 
observations, are necessarily liable to some error, from the im- 
perfect manner in which their observations were made, most of 
them having been but approximations, and not very close ones, 
to the truth. We have illustrated, (page 60), in what manner 
the precession of the equinoxes causes the pole of the heavens to 
revolve around the pole of the ecliptic, the effect of which is, that 
successive stars, which lie in the circumference of the circle 
which the pole of the heavens thus describes, will, in succession, 
become the pole star. The present polar star was not always the 
pole star, nor is it as near the true pole of the heavens now, as it 
will be. In about 240 years, it will be but 29' 55" distant from 
the pole. At the time of the earliest catalogues, it was 12° dis- 
tant, and now, 1848, its distance is about 1° 25'. About 2900 
years before the commencement of the Christian era, the bright 
star in the tail of Draco, called Alpha, was the polar star, and was 
then only 10' from the pole ; and in 11,600 years, the bright 
star Lyra, will become the polar star, and will then be but 5° from 
the pole, whereas, its distance now is upwards of 51°. We give 
on the next page, a representation of that part of the heavens 
where the north pole of the ecliptic is situated. 

Here we have the pole of the ecliptic in the centre, and the 



POLE OF THE ECLIPTIC. 



89 



pole of the heavens, or that part of the heavens towards which 
the pole of the earth points, at the top, directly where the line VI- 
XVIII crosses the outermost circle drawn around the pole of 
the ecliptic, and which is the little circle represented in the figure, 
(page 59), with the radius T S, or T Z. The pole of the earth, as 




it revolves around the pole of the ecliptic, passes, in succession, 
through each point of this circle, moving, as represented in the 
map, towards the left. This circle we have graduated into spaces 
of ten degrees each, and drawn meridians from the pole of the 
ecliptic through them, the pole of the heavens moves over one of 
these spaces in about 718 years. The meridian VI, XVIII, is the 
only one which passes through the two poles, consequently when 
Polaris comes to this meridian, its distance from the pole will be 
the least possible. In the course of 2100 years, as will be perceived. 



90 THE WORLD. 

the star called Gamma, in the constellation Cepheus, will be the 
poie star. The meridian VI, XVIII, is called the solstitial colure, 
because it is the meridian which passes through the highest and 
lowest points of the ecliptic, which are called solstices, being the 
meridian 18, P, 6, of the figure on page 91. 

We will now give some instances of the application of the pre- 
cession of the equinoxes to chronology. Eudoxus, a celebrated 
Greek astronomer, informs us, that in the celestial sphere, he had 
observed a star which corresponded to the pole of the equator. 
From various circumstances, we know Eudoxus lived about 
the fourth century before Christ, hence it could not be our present 
polar star which he observed, for at that time it was too far re- 
moved from the pole. Upon reckoning back about 2000 years, 
however, upon our map, we find a small star of the fifth magni- 
tude, which may be the one observed by Eudoxus. We are of 
opinion that this star is the one meant by him. Others, however, 
supposing Eudoxus to have borrowed his sphere from some older 
source, have selected Kappa, in the constellation Draco, as the 
star. This latter was the pole star about 1310 years before Christ, 
but in the time of Eudoxus, it was as far distant from the pole, 
nearly, as was our present polar star. The little star we have been 
considering, was the pole star about 200 years before the Christian 
era, and as it is easily visible to the unassisted eye, was probably 
the star meant by Eudoxus. 

The effect of the precession of the equinoxes, is to change the 
right ascensions and declinations of the stars, for, as we have 
more than once observed, right ascension is the distance from the 
first point of Aries, but this point is continually changing its place 
in the heavens. It also changes what is called the longitude of 
the stars. The longitude of a star, is, like right ascension, 
reckoned from the first point of Aries eastward, but upon the 
ecliptic instead of the equator, thus, 0° of R. A. and 0° of Long, 
are both reckoned from the same poii)t. See the next figure, 
where the right ascension is marked 0, 1, 2, 3, 4, &c, and 
longitude is marked 0, I, II, III, IV, &c. Declination is distance 
north or south of the equator, but latitude is distance north or 
south of the ecliptic, hence, when a star happens to be in the 



PRECESSION OF THE EQUINOXES. 



91 



meridian called the equinoctial colure, or meridian which passes 
through the equinoxes, a part of which meridian is seen at P O, its 




declination and latitude will be pretty near the same, but if the 
star happens to be in the solstitial colure, the latitude will vary 
from the declination, by the amount due to the obliquity of the 
ecliptic, being either more, or less, according to the position of 
the star, and whether the latitude is reckoned north or south. It 
will also appear that the latitude of a star is not altered by preces- 
sion. Imagine, for a moment, the system of meridians, and the 
ecliptic and equator, entirely detached from the stars, and moved 
slowly around, not the pole of the earth, which we will imagine 
within it, but the pole of the ecliptic H. It is easy to conceive 
that a star which is in the equator, say at the point 2, would no 
longer be in it, but a star at II, in the ecliptic, although its distance 
from the vernal equinox would be increased, would still be in the 
ecliptic. The same is true of all small circles parallel to the 
equator and ecliptic, the former called declination circles, and the 
latter parallels of latitude. Perhaps we have been tediously mi- 
nute, but there is some satisfaction in understanding a difficult 
subject, and if the reader has had like patience with ourselves, 
we trust the time will not be spent in vain. The grand point at 
which we have been aiming, after all, is this : if we can find any 
ancient records of observations which give the longitudes of the 
stars, we can tell the dates of the observations. It is well known 
that the ancients did not possess a uniform system of chronology 



9& THE WORLD. 

like ourselves, but they endeavored to perpetuate the memory' of 
great events by recording the positions of the heavenly bodies at 
the time ; and in this, at least, they exhibited wisdom. We find 
continual evidences of this, particularly in the poets of those early 
ages. The Egyptians, to whom the overflowing of the Nile was 
an annual, and in some respects, a dreaded occurrence, were ac- 
customed to watch for the heliacal rising of the dog-star, which 
warned them to gather their wandering flocks and herds, and 
prepare for the coming flood* Hence, that star was called Thoth, 
the watch-dog, the Guardian of Egypt. 

The stars rise or set heliacally, when they rise just before, or 
set just after the sun. They are said to rise or set cosmically, 
when they rise or set just at sunrise, and to rise or set acronycally 
when they rise or set just at sunset. It will appear that the heliacal 
rising, or setting, will precede or follow the cosmical rising, or the 
acronycal setting, b)?- about 12 or 15 days, for a star cannot be seen 
unless the sun is 12° or 15° below the horizon, and the sun 
moves over about a degree in a day. Pliny says that Thales, the 
Miletian astronomer, determined the cosmical setting of the 
Pleiades to be 25 days after the autumnal equinox. At the present 
time, the same event occurs about 60 days after the equinox, 
making a difference of 35 days, which, allowing 59' to a day, 
makes 34° 25' change in longitude, due to the precession of the 
equinoxes. This, divided by the annual precession, 50.2' ', gives 
about 2465 years since the time of Thales, or 620 years before 
Christ. We find, also, in Hesiod, the number of days after the 
winter solstice, when Arcturus rose acronycally, 

" When from the solstice sixty wintry days 
Their turns have finish'd, mark, with glitt'ring rays, 
From Ocean's sacred flood, Arcturus rise, 
Then first to gild the dusky evening skies." 

But as we know the latitude of Bceotia, where Hesiod lived, we 
can determine the acronycal rising of Arcturus, and by means of 
the difference between the time now, and the time mentioned by 
him, which is due to precession, can determine the age in which 
he flourished. From actual observation, it is ascertained that now 
this star rises at sunset about 100 days after the, winter solstice. 



PRECESSION OF THE EQUINOXES. iJJ 

The difference, 40 days, converted into degrees, allowing 59' for 
a day, is 39°, very nearly ; dividing this by the annual precession 
50.2' ; , gives 2796 years since he nourished, or about 950 years 
before the Christian era. Meton, the famous astronomer of Athens, 
says that the star Beta Arietis, was in the vernal equinox in his 
time, but at the commencement of the present century its longitude 
was 31°, 10', 44", this divided by the annual precession, gives 
2236 years from the time of Meton's observations to the commence- 
ment of the 19th century, or 436 years before Christ. If we know 
the year in which any event occurred, we are frequently enabled 
to tell nearly the day on which that event transpired. Thus, 
Thucydides tells us that the investment of Platea, during the fifth 
year of the Peloponnesian war, which was 426 years before the 
Christian era, occurred about the time of the heliacal rising of 
Arcturus. But the heliacal rising of Arcturus then occurred in 
the month of August, and hence we are enabled to not only give 
the year, but nearly the month when this event occurred. And 
we may here remark, that the beginning of the Peloponnesian 
war, is itself, determined to be 431 years before Christ, by means 
of an eclipse of the moon which occurred, as can be most accu- 
rately calculated, April 25th. In the same year, on the 3d of 
August, an eclipse of the sun was visible at Athens, concerning 
which, Thucydides, the celebrated Greek historian, remarks : 
that a solar eclipse happened on a summer's day, on the after- 
noon, in the first year of the Peloponnesian war, so great that the 
stars appeared. 

" We are apt to undervalue the science of the ancients; we 
ought rather to look upon it with respect and admiration. It is truly 
astonishing that with their imperfect instruments, they arrived at 
so much accuracy in their astronomical calculations. The very 
want of instruments led to an intensity of observation much 
greater than ours. As the savage inhabitant of the forest with- 
out a compass, marks his course through the pathless wilds with 
an accuracy far beyond that of the civilized man, so at a very 
early period of the world's history, did even barbarous nations 
learn by the rising and setting of the constellations to regulate the 
course of the year. However rude therefore, the Romans under 

E* 



94 THE WORLD. 

Romulus may have been, it was impossible for them to depart 
greatly from the tropical year; because they watched the constel- 
lations, and connected with their rising and setting the seasons 
of agriculture, and the times of their religious festivals. Any 
alterations would be quickly perceived and the very observances 
of a religion, the gods of which presided over their secular em- 
ployments, served as a balance-wheel to regulate the movements 
of their chronology." 

We shall conclude this chapter with some account of the Zodiacs 
discovered by the scientific men who accompanied the French 
expedition to Egypt, and which were thought to give an age to 
the world much greater than the generally received system of 
chronology. We may here remark, that the evidence appears 
from other sources, to be pretty conclusive, that man has not in- 
habited the globe for more than about 6000 years, although the 
evidence is equally strong, that the globe itself, is, perhaps, 
millions of years old, and has been inhabited by a race of animals, 
and covered with a vegetation, entirely unknown at present. During 
the campaigns of the French army in Egypt, a Planisphere and 
Zodiac were discovered by Mons. V. Denon in the Great Temple 
of Dendera, or Tentyra, and copied in his «* Voyage dans la Basse 
et la Haute Egypie, pendant les Campagncs du General Bona- 
parte.': Paris, 1802, Fol. Vol. II. Plates, 130, 131, 132. Den- 
dera, anciently the large city of Tentyra, is a town of Upper 
Egypt, situated at the edge of a small but fertile plain, about a mile 
from the left bank of the Nile, and 242 miles south of Cairo. Its 
Temple, magnificent even in ruins, is the first that the Egyptian 
traveler discovers on ascending the Nile ; it is 265 feet in length 
and 140 feet in breadth, and has 180 windows, through each of 
which the sun enters in rotation, and then returns in a retrograde 
direction. The front of the Temple is adorned with a beautiful 
cornice and frieze, covered with hieroglyphics, over the centre of 
which is the winged globe ; while the sides are decorated with 
compartments of sacrifices. In the front of the building is a 
massive portico, supported by 24 immense columns, in four rows, 
having circular shafts covered with hieroglyphics, square capitals 
resembling Egyptian Temples supported by four human heads 



EGYPTIAN ZODIACS. 95 

horned, and round foliated bases on square plinths. On the ceiling 
of this portico is the large Zodiac, partly carved and partly 
painted in natural colors, on a blue ground studded with yellow- 
stars. The general design of the Zodiac is divided in two, and 
represents two female figures, which bend over the divisions, 
typical of Isis, or the year ; with a winged globe placed against 
each, allusive to the sun entering his course. Each band of the 
Zodiac is divided into two, by a broad line covered with smaller 
hieroglyphics. On the upper division of the Zodiac, which is the 
broadest, are represented six of the Zodiacal signs ; and under 
them, in the second division of the top band, are 19 boats, each 
carrying a figure significative of some astronomical appearance ; 
accompanied by an Egyptian inscription in a square. The con- 
stellations, and other heavenly bodies, were the Divinities of 
Egypt, and it was supposed that they performed their revolutions 
in boats. The other great band contains the six remaining signs 
of the Zodiac ; and on its lower division are 19 other boats, as 
before. The Rev. Samuel Henley, in his very instructive and 
highly erudite remarks on this Zodiac, published in the Monthly 
and Philosophical Magazines, says, that these boats signify the 
nineteen years of the Metonic, or Lunar Cycle, which contains 
6940 days ; after which, the New and Full Moons, and other 
Aspects, are supposed to return to the same day of the Julian year. 
The smaller Zodiac, or rather Planisphere, is carved on the ceiling 
of a separate quadrangular apartment on the east side of the Temple. 
It is of a circular form, and is supported by four human figures, 
standing, and eight kneeling,who have hawks heads. In both these 
Zodiacs the equinoctial points are in the constellation Leo, and it 
was by some inferred that they were constructed at the time when 
the sun entered this constellation at the equinox, or more than 9,700 
years ago ; about 4,000 years before the Mosaic record. These 
Zodiacs were brought away, and exhibited in the Louvre at Paris ; 
and for a long time were the occasion of much discussion. All 
the speculations of infidel philosophers were, however, scattered 
to the winds by the discoveries of Champollion ; and the disserta- 
tions of Visconti and Henley have proved, in opposition to the 
infidel arguments of Ripaud. Petau and Archer, that they are of 



96 



THE WORLD. 



the age of Augustus Ceesar ; and that they were erected in the 
Julian Year 4695, which then regulated the Egyptian , twenty- 
four years before the actual birth of our Savior, and twenty-eight 
years before the common era. All this is confirmed by the fol- 
lowing Greek inscription, over the outer or southern portal of the 
Temple : — " On account of the Emperor Caesar, God, the son 
of Jupiter, the Deliverer, when Publius Octavius being Governor, 
Marcus Claudius Posthumus Commander in Chief, and Tryphon 
General, the Deputies of the Metropolis consecrated, in virtue of 
the Law, the Propylaeum to Isis, the greatest of Goddesses, and 
to the associated Gods on the Sacred Thoth." The Country of 
Egypt, had at that time become a Romish Province ; and Augus- 
tus Caesar, in the 31st year of his age and the 725th year of Rome, 
ordained that the Egyptian Thoth should for ever commence on 
the 29th of August. 



THE SEASONS. 97 



CHAPTER VIII. 

The Seasons. 

" For this the golden sun the earth divides, 
And, wheel' d through twelve bright signs, Tiis chariot guides, 
Five zones the heaven surround; the centre glows 
With fire unquench'd and suns without repose: 
At each extreme, the poles in tempest tost, 
Dark with thick showers and unremitting frost: 
Between the poles and blazing zone confined, 
Lie climes to feeble man by Heaven assigned. 
'Mid these the signs their course obliquely run, 
And star the figured belt that binds the sun." 

Sotheby's Virgil. 

We have, at length, arrived at that part of our work, which will 
treat upon and explain the phenomena of the seasons. All that 
we have said in the preceding chapters, has been preparatory to 
this, and, we trust, that there will not be less of beauty, or poetry, 
in our contemplations of those great changes which mark the 
rolling year, because we can understand the causes which produce 
them. To our own mind, there is no subject more delightful 
than this, of the changing year ; a theme, which is perhaps, still 
more endured to us by the beautiful poetry of a Thompson, a 
Bloomfield, and a Cowper. A theme, which, even to Chaucer, 
and Spenser, and Shakspeare, and Milton, was a passion. 

After the somewhat tedious detail and explanation, which has 
preceded, we feel, on approaching this always interesting subject, 
as Milton expresses it, 

" As one who long in populous cities pent, 
Where houses thick and sewers annoy the air, 
Forth issuing on a summer morn, to breathe 
Among the pleasant villages and farms.** 

To behold Nature as she is, and see the glorious changes which 
she wears, from the unsullied mantle of winter to the russet garb 
of autumn, we must quit the busy haunts of men, and leaving the 



98 THE WORLD. 

noisy streets and smoky cities, seek the country fields, and lanes. 
We have been much struck with a remark of Howitt, in his 
" Book of the Seasons," in which he thus deprecates the necessity 
that deprives our childhood of a contemplation of those beautiful 
changes which mark the year. "Oh that I could but touch a 
thousand bosoms with that melancholy which often visits mine, 
when I behold little children endeavoring to extract amusement 
from the very dust, and straws, and pebblos of squalid alleys, 
shut out from the free and glorious countenance of Nature, and 
think how differently the children of the peasantry are passing the 
golden hours of childhood ; wandering with bare heads, and un- 
shod feet, perhaps, but singing a 'childish, wordless melody,' 
through vernal lanes, or prying into a thousand sylvan, leafy 
nooks, by the liquid music of running waters, amidst the fragrant 
heath, or on the flowery lap of the meadow, occupied with winged 
wonders without end. Oh ! that I could but baptize every heart 
with the sympathetic feeling of what the city pent child is con- 
demned to lose ; how blank, and poor, and joyless must be the 
images which fill its infant bosom, to that of the country one, 
whose mind 

Will be a mansion for all lovely forms, 

His memory be a dwelling-place * 

For all sweet sounds and harmonies! n 

In the absence of a system of chronology to mark the returning 
periods of nature, the ancients were obliged to note the aspects of 
the stars. We have several times, in the preceding pages, referred 
to this, and we may now remark, that some of the most beautiful 
passages of the ancient poets, contain allusions to the stars as 
connected with agriculture. Ilesiod, the oldest poet of the 
Greeks, has given a minute detail of the heliacal rising of the 
stars, accompanied with the most pleasing descriptions of the 
successive occupations of rural life. The name of the poem is, 
"Opera et Dies," the Works and Days. This poem Virgil has imi- 
tated, in the first and second M Georgics ;" a word compounded 
of two Greek words, and meaning, works or labors of the earth, 
and corresponding almost exactly with our word agriculture. We 
shall give occasional quotations from both these poems, in our 
present chapter. 



SIGNS OF THE ZODIAC. 99 

Iii the absence of a correct calendar, such as our almanacs now 
furnish, the early cultivators of the soil very wisely determined 
the recurrence of various seasons, by the aspect of the heavens. 
It was, to them, a matter of no small importance, to know, with 
unerring certainty, the time when first to break the soil, and plant. 
This they could not do, judging from the simple change in the 
climate, or temperature, due to the return of spring ; as various 
causes, which we need not mention, render this indication liable 
to great uncertainty. Hence, at a very early day, the apparent 
path of the sun, in the heavens, was divided into twelve portions, 
called signs ; and as these signs were mostly representatives of 
living objects, it was called the Zodiac, from a Greek word 
meaning life. In a previous chapter, we have shown how this 
division was accomplished by means of the water-clock. The 
present division of the Zodiac was probably made by the Egyptians, 
and they named the signs with particular reference to agriculture, 
and the seasons at the time of their invention. From the 
Egyptians it was undoubtedly borrowed by the Greeks, and from 
them has been transmitted to us. As we have elsewhere shown, 
these signs are reckoned from the point of vernal equinox, or first 
point of Aries, eastward, completely around the ecliptic. Their 
names are, Aries, Taurus, Gemini, Cancer, I^eo, J'irgo, Libra. 
Scorpio, Sagittarius, Capricomus, Aquarius, Pisces. The sun 
enters Aries, or the Ram, at the time of vernal equinox ; hence 
this sign was represented under the form of a ram, to which 
the character °p was placed, designed no doubt, at first, to repre- 
sent a ram's horns. This was the beginning of spring. The 
sun entered the next sign, Taurus, a Bull, a month afterwards : 
which was, therefore, appropriately represented by a bull, the 
attention now being drawn to plowing and sowing. This sign 
was once situated in the co)isiellat/o)i Taurus, which numbers 
among its stars the beautiful group called the Pleiades, or seven 
stars, although now, on account of the precession of the equinoxes, 
it is in the constellation Aries. Hesiod alludes to the heliacal 
rising and cosmical setting of the seven stars : 

"When, Atlas born, the Pleiad stars arise. 
Before the sun, above the dawning skies, 
'Tis time to reap : and when they sink below 
The morn illumined west, 'tis time to sow." 



100 THE WORLD. 

And we find in Job an allusion to the Pleiades, as harbingers 
of spring : " Canst thou bind the sweet influences of the 
Pleiades," &c. [Job 38 : 31]. The symbol of Taurus is tf , once 
intended for a bull's head and horns. The sign Gemini, or the 
Twins, which the sun enters two months after the commence- 
ment of spring, was denoted by the symbol JJ, intended to 
represent the twin sons of Leda ; as this was the month when the 
flocks brought forth, this sign was adopted as the harbinger of a 
fruitful increase. The next sign is Cancer, the Crab, the sun 
enters this sign at the time of the summer solstice, or at mid- 
summer. Previous to entering this sign, it had been rising, each 
day, higher and higher, until now, having reached its highest 
point, it begins to return ; hence the sign, a crab, an animal 
fabled to run backwards as well as forwards, and its symbol 55, is 
intended to illustrate this. In the Zodiacs discovered at Dendera 
and Esne, alluded to in the last chapter, the place of this sign is 
occupied by a Scarabeus, or Beetle ; but in the Hindoo Zodiac, 
which was probably borrowed from the Chaldeans, and is therefore 
older than the Egyptian, we find the figure of a crab, It will be 
understood tliat these divisions of the ecliptic, which heretofore 
we have marked as hours, see the figure, page 91, are the com- 
mencement and middle of the twelve signs, each sign compre- 
hending two hours, corresponding to the first point of Aries, II 
the first point of Taurus, &c. It will be noticed that the sun 
reaches the highest point of his orbit at VI, or the first point of 
Cancer, where the solstitial colure intersects the ecliptic. 

The fifth sign is- Leo, the Lion. The sun entered this sign 
about the time of the overflowing of the Nile, at which period, the 
lions, driven from the interior by the heat, hunted along its banks. 
This sign is figured in the Egyptian and Indian Zodiacs 
very near as we have it now. The symbol is <$\,,, probably a 
corruption of an hieroglyphical character, intended for a crouching 
lion. The next month, the sun entered Virgo, the virgin. This 
was the harvest month, and hence was appropriately represented 
by a virgin with a sheaf of wheat. The Egyptians represented 
it under the figure of Isis; the symbol is ffJJ. This is probably an 
hieroglyphical character. The next sign is Libra, the balance, 



ZODIAC. 101 

represented by a scale-beam =^= . The sun enters this sign at the 
time of the autumnal equinox, when the days and nights become 
nearly equal all over the world, as we shall soon explain. Virgil 
alludes to this constellation : 

" When poising Libra rest and labor weighs, 
And parts with equal balance nights and days, 
Goad, goad the steer, the barley seed enclose, 
Till winter binds the ground in dead repose." 

The next month, abounding with venemous reptiles, was 
characterized by the sign Scorpio, a. scorpion, though in some of 
the old Zodiacs it is represented under the form of a snake, or an 
alligator; its symbol is fT^. The next sign is represented, in all 
the Zodiacs, under the form of a hunter, or archer, as the sun 
enters this sign in November, the hunting month, and its symbol 
is an arrow f. When the sun enters the next sign, about the 
latter part of December, it is mid-winter, and the time of the 
winter solstice, the sun being at the position marked XVIII, see 
the figure, page 91. It is represented under the form of a goat, 
for now the sun, having reached its lowest southern declination, 
begins to climb up in the heavens, like the goa^ climbing the 
mountain steeps ; the symbol is "[{J. The next sign is represented 
by Aquarius, the water-pourer, perhaps in allusion to the rainy 
season, and the symbol,^, is intended, no doubt, to represent the 
water, or waves. The last sign is Pisces, the fishes, represented 
by the symbol)^, and the constellation is usually figured in the 
heavens as two fishes tied by their tails, for the earth being now 
bound in winter's icy chains, subsistence is derived from the 
streams. 

Such are the twelve signs of the Zodiac, and through one of 
these the sun passes each month, and thus their names, become 
to us, indicative of months, Aries corresponding with March, 
Taurus with April, &c. When the sun enters one sign the earth 
enters the opposite, as in the following diagram. 

Thus, when the earth enters the sign Libra at C, at the time of 
the vernal equinox, the sun, S, appears to enter the -opposite sign. 
Aries, at A, and when the earth arriving at D, enters the sign 
Capricornus, at the time of the summer solstice, the sun enters 






102 THE WORLD. 

the opposite sign, Cancer, at B. Hence, whatever sig-n the sun 




may be in, the opposite sign will rise at sunset, being 180°, or 
half a circle, distant from the sun. If the orbit of the earth was 
a true circle, tlfe progress of the sun through the signs would be 
performed with an equable motion ; but this is not the case, as we 
have shown when speaking of the equation of time. Its orbit is 
elliptical, and its major axis lies in the direction of a line joining 
the beginning of August and January, nearly, so that the sun is 
actually nearer the earth in January than in August. We shall 
see, presently, why its rays, at that time, have less effect in 
warming the earth, in our northern climates than in summer. 
On account of the proximity of the earth, to the sun, in winter, 
and its consequent swifter motion ; the sun will appear to move 
through the winter signs faster than through the summer signs, 
and will therefore accomplish the six winter signs quicker than 
the six summer signs. Hence, the winter is always, in any latitude 
north of the equator, shorter than the summer. This difference 
amounts, in the temperate zones, to almost eight days. At all 
places south of the equator it is summer, when it is winter in the 
northern hemisphere, as we shall now proceed to show, and 
hence the summer there is shorter than the winter, for the sun is 



LINE OF APSIDES. 103 

nearest those places in summer. And those signs, which are 
winter signs to us, who live in the northern hemisphere, are 
summer signs to the inhabitants of the southern. All varieties of 
seasons are thus, at all times, upon our globe. When one portion 
is covered with the white mantle of winter, another is producing 
beautiful flowers. At one place spring is commencing, at another 
the autumn, and around the equatorial regions of the earth per- 
petual summer reigns. Perhaps there is nothing that seems more 
strange to the traveler, than this variety of seasons from change 
of latitude. The names of the winter months, which so long 
have been associated with ideas of cold, and frost, and storm, seem 
strangely misplaced, when he beholds flowers blooming around 
him in December, and hears the songs of birds wafted on the 
light breeze. Christmas and New Years, which in our northern 
country, are wont to be associated with the cheerful blaze, the 
merry sleigh -ride, or the drifting snow, bring no such associations 
to the inhabitant of the southern hemisphere ; there, mid-summer 
reigns, and the cool breezes, which blow over the Indian seas, 
laden with perfume, dispel the sultry heat. The cause by which 
all this variety is produced, is not the less interesting because it is 
simple, and because we see in it a guaranty that long as time shall 
last, or the present race inhabit the globe, so long the seed 
time and harvest must return with undeviating certainty. 

We have mentioned formerly that the earth's orbit is an ellipse, 
and that the longer or major axis of the ellipse is called the line 
of the apsides. We might have shown that between the limits of 
an ellipse, viz: a perfect circle on the one hand and a straight 
line on the other, this orbit might vary, but still the periodic 
time of a revolution remain unchanged. But these are theoreti- 
cal investigations upon which we cannot enter. We will, how- 
ever, observe that the line of the apsides, or major axis of the 
earth's orbit, is its most important element, for when this is de- 
termined the periodic time of a revolution, and the mean distance 
from the sun are also determined. The orbit itself, under the 
influence of various forces, may change its ellipticity, expanding 
towards a circle on the one hand, or diminishing towards a 
straight line on the other, or the ellipse may swing round upon 



104 THE WORLD. 

this line, altering its position in space; but amidst all these 
changes, the line of the apsides knows no change. Its length 
remains the same notwithstanding all the perturbations of the 
planets, and all the changes to which the rest of the orbit may be 
subjected. The eccentricity of the earth's orbit is now slowly 
changing, diminishing at the rate of about 11" in a century, on 
account of the mutual gravitation of the planets. It will continue 
to diminish for centuries, and it is somewhat curious that this 
dimunition is indicated by the movements of the moon, . for it 
produces, as we have remarked before, no effect upon the period- 
ic time of a revolution of the earth. It is now pretty well deter- 
mined that the motion of the moon is continually accelerated. 
Upon comparing observations made at distant intervals, it is found 
that the Chaldean and Alexandrian observations give a longer 
period, than the Alexandrian and Arabian of the eighth century; 
and a comparison of the Arabian and modern observations, gives a 
still shorter period. These variations are all periodical, and are 
compensated in opposite points of every period, the mean distan- 
ces, and mean periods, will always remain the same. "Cold, 
we think, must be the heart that is not affected by this mark of 
beneficent wisdom in the contriver of the magnificent fabric." 



INCLINATION OF THE EARTH'S AXIS. 



CHAPTER IX. 

The Seasons. 



105 



" These, as they change, Almighty Father, these 
Are but the varied God. The rolling year 
Is full of thee." Thompson. 

Throughout the preceding chapter, we have spoken of the 
plane of the orbit of the earth as inclined to the plane of the equa- 
tor. As a necessary result of this, the axis of the earth points, at 
all times, towards the same point of the heavens, with the ex- 
ception of the slight motion caused by the precession of the 
equinoxes. This is a fact, with which we are all familiar, for we 
know the pole star is the star towards which the axis of the earth 
points throughout the year. Thus, in the following diagram, let 




A B C D, represent the earth in four different positions in its 
orbit. Now, if the axis of the earth was perpendicular to the plane 
of the orbit, as shown in the diagram, then the plane of the equa- 
tor, a, b, would correspond with the plane of the orbit, but, as the 
plane of the equator manifestly does not correspond with the plane 
of the ecliptic, the axis of the earth must be inclined to the plane 
of its orbit, as in the next diagram, and this inclination it main- 
tains throughout its entire revolution around the sun, its axis 
always pointing towards the polar star. Of course, in our diagram, 
this does not appear to be strictly the case, as we cannot repre- 
sent the star removed to a sufficient distance. The inclination of 
the axis of the earth to the plane of the sun's apparent path, is the 
cause of all the variety of the seasons ; of the differing lengths 
of the nights and days ; and the daily changes of the sun's decli- 
nation. If the earth's axis had been placed perpendicular to the 



106 



THE WORLD. 



plane of the ecliptic, then, at all seasons of the year, the days and 




nights would have been equal all over the world, for, as will be 
seen on reference to the figure on page 105, the sun would shine 
from pole to pole, and as it would illuminate but half the globe at 
once, a spectator any where on its surface, would be just as long 
in passing through the unilluminated as the illuminated portion. 




Thus, a spectator at A, on the parallel of latitude B C, would be 
just as long in moving through the half of the unilluminated por- 
tion of the earth B A, as through half the illuminated A C. This 
is the case at the equinoxes. When the sun is in either of those 
points of his orbit which crosses the equator, then it illuminates 
the globe from pole to pole, i. e. when he is in either of the points 
0, or XII, see the figure on page 91. We have already shown 
that the apparent diurnal path of tbe sun through the heavens due 
to a rotation of the earth upon its axis, is in what is called a diurnal 



DECLINATION OF THE SUN. Hi . 

circle, or a circle parallel to the equator ; hence, at the time of 
the equinoxes, the sun will, apparently, in his diurnal circle in 
the heavens, move in the equator ; and as the successive meridians 
come under, it will appear directly over head, or vertical, at noon, 
to a person any where on the equator. As the globe turns around, 
the sun now passes directly over the islands of Sumatra and 
Borneo, and the islands in the midst of the Pacific ocean ; also 
over the northern part of South America, the middle of Africa, 
and the Indian ocean. We will suppose it is the time of the au- 
tumnal equinox, when the sun enters Libra, or is in the position 
marked XII, in the figure on page 91 . A month after, the sun 
has moved to the position XIV. And as the earth turns around 
on its axis, it appears no longer vertical, or over head, at the 
equator, at noon, but to those places situated on the parallel ef, 
over the islands of New Guinea and Java; the middle of South 
Africa ; the top of the Brazils ; and, perhaps, the Society, and 
the Friendly islands. As the sun moves still farther on in its 
orbit, to the position VI, it appears now vertical, or over head, at 
noon, to an observer on the parallel g h, and as this is the greatest 
distance from the equator, and therefore farthest south where it 
can be vertical, at noon, and, as after this, it again approaches 
the equator, this point is called the solstitial point, i. e. the point 
where, having reached its greatest southern declination, the sun, 
apparently, for a few days, remains still, or at precisely the same 
altitude at noon, for a few days, and then begins to return ; this 
limiting parallel on the earth is called the tropic of Capricorn, for 
it is now January, the time of the winter solstice, when the sun 
enters the sign Capricorn. The earth is now illuminated by the 



^=^JL 



sun, as shown in this diagram. The sun being vertical at noon , 



108 THE WORLD. 

to all places on the parallel C D, it will be observed that it is now 
summer in the southern hemisphere, and that there, the days are 
now longer than the nights, the illuminated portion C G, being 
greater than the shaded portion G D. At the equator, however, 
the days and nights are still equal, but in the northern hemis- 
phere it is mid- winter, and the days are shorter than the nights, 
as the arc E H, is shorter than the arc H F, the former represent- 
ing half the day, the latter half the night. Here, then, is the 
explanation of the short days in winter, and the long nights, and 
it will also be seen that, to an observer any where in the northern 
hemisphere, the sun will come to the meridian very low down . 
It will also be noticed, that the shadow of the unilluminated por- 
tion of the earth, falls entirely beyond, or without the antarctic 
circle I K, and includes the arctic circle L M. To an observer, 
therefore, within the southern polar circle, the sun now never 
sets. Three months before, when the earth and sun were in the 
positions shown in the figure, page 106, the sun rose a short way 
above the horizon, within each circle, but each succeeding day 
he sank lower and lower, to those within the arctic or northern 
polar circle, and rose higher and higher to those within the an- 
tarctic circle, so that now, begins the long day of the latter, and 
the long night of the former. It would be a curious sight to an 
inhabitant of the more temperate zones, to see the sun thus 
gradually mounting above the horizon, moving completely around 
without setting, and visible during the whole day, for nearly six 
months. Although darkness reigns at the other pole, so far as 
the direct rays of the sun are concerned, yet the long night is en- 
livened by the bright moon light, which reflected from a thousand 
hills of snow, sheds a bright light around, and the planets and 
stars in that cold region, where no mists ever obscure the sky, 
twinkle in the clear firmament like diamonds. The bright cor- 
ruscations of the Aurora, with changing and fanciful lights, are 
there seen in their greatest perfection, and cheer, with their 
varying forms, the hunters who penetrate within the icy circle ; 
and here nature is seen in some of her grandest forms. Huge 
mountains of ice, formed by the winters of centuries, rear their 
Alpine summits to the sky, and life in singular forms, sport on its 



VRE SEASONS. 



109 



uold surface, or beneath the colder waves. The Polar Bear, and 
the huge Walrus, and the -Seal, sport among the floating fields of 
ice; and the great Auk, or Penguin, seems to choose, by instinct, 
this desolate and almost forsaken region of the earth. 

As the earth moves on in its orbit, the sun now rises higher 
and higher in the heavens, at noon, each day, and finally arrives 
at the point of vernal equinox and enters the constellation Pisces. 
Again the nights and days are equal all over the globe, the earth 
being illuminated from pole to pole. As the sun proceeds still far- 
ther north of the equator, the north pole becomes more and more 
illuminated, until finally it arrives at the point of greatest differ- 
ence between the equator and ecliptic marked XVIII, see figure on 
page 91, which is the point of the summer solstice. The sun is 
now vertical in the northern hemisphere, at noon, at all places 
situated on the parallel a b, which is called the tropic of Cancer. As 
the sun is now entering the sign Cancer, and since the north pole 

3? 




of the earth is now wholly illuminated, as in the above diagram, 
it is evident that the north pole, or rather the axis of the earth, is 
inclined towards the sign Cancer. The days are still equal to the 
nights, at the equator, but at all places north of the equator, as for 
example on the parallel A B, the days are now longer than the 
nights, the half illuminated portion I B. being greater than the 
half unilluminated A I. It is now mid-summer, the beginning 
of July, in the northern hemisphere, while at the same time it is 
mid-winter in the southern. The arctic circle is now wholly illu- 
minated, but the antarctic is in complete shade. At this season 
the sun mounts highest in the heavens to all north of the equator, 
and lowest to all south of it. The rays of the sun falling almost 
direct, or perpendicular, upon the earth, in our northern latitude 



110 THE WUELB. 

in summer, and also the days being longer than the nights, and 
the earth being thus warmed during the day more than it is cooled 
during the night, this excess of warmth contributes to augment 
the summer heat. It will also now appear why, although 
the earth is actually nearer the sun in winter than in the 
summer, no increase of heat is, on this account, perceived, as the 
rays, at this time, fall very slanting upon the earth in the northern 
hemisphere, although in the southern hemisphere, the summer 
occurring at the time when the sun is nearest the earth, is much 
warmer than the same season at the north. The lines we have 
thus seen, apparently marked on the earth by the sun, divide the 
earth into five zones, or belts. The north frigid; the north tem- 
perate; the tropical, or torrid; the south temperate; and the south 




frigid* The first and last are included within the polar circles, 
and are always cold, inhospitable regions. The temperate zones 
are included within the polar circles and the tropics, whilst the 
tropical, or equatorial regions lie wholly within the two tropics. 
At the equator, as we have already intimated, and indeed for 
some distance north and south, nearly to the tropics, perpetual 
summer reigns, as the sun is, at almost all times vertical at noon; 
at the equinoxes, it is truly so ; but at the time of the summer 
solstice, it is seen by the inhabitants of the equatorial regions 
passing between the zenith and the northern horizon, not, how- 
ever, nearer the north pole, or the polar star, than the rest of the 
world perceive it ; for to them, the north star is on the horizon. 
At the time of the winter solstice, it is seen by a spectator at the 



CHANGE OF THE LINE OF APSIDES. Ill 

equator, to pass between the zenith and the southern horizon, 
about as far from being vertical at noon there, as it is to us at 
the time of summer solstice. Hence, an observer there, looking 
directly overhead, might imagine the equator a line marked in 
the heavens extending from east to west, like the line E W; Z 



being the zenith, or point directly overhead, and A B the sun's 
path, along which it would appear to move; being at Z, at the 
time of the equinoxes, rising directly east and setting directly west, 
and at B at the time of the summer solstice, describing, by the 
diurnal motion of the earth, the tropic Cancer, and at A at the 
time of winter solstice, its diurnal path being the tropic of 
Capricorn. 

We have thus, at some length, explained the phenomena of the 
seasons, and will now, for a few moments, consider what will be 
the effect of the precession of the equinoxes. The earth's axis, 
at present, is inclined towards the sign Cancer, which is located 
in the constellation Gemini. In the course of about 6000 years, 
it will still be inclined towards the sign Cancer, but that sign will 
be in the constellation Pisces. And in 6000 years more, towards 
the constellation Sagittarius. In consequence of this change, 
the seasons will all, really, be misplaced about six months, although 
the various contrivances for retaining the names of the months, 
as indicative of the several seasons, will doubtless, then, as now, 
make the 21st of March the commencement of spring, or time 
of vernal equinox. There is, however, a more important change 
than this, which will affect our seasons The major axis of the 
earth, or line a b, see figure on page 78, has not a fixed direction 
in space, but is slowly moving from west to east, i. e. in the order 
of the signs, at such a rate that it will require about 100,000 years 
to make a complete revolution, The earth arrives at its perihelion 



112 THE WORLD. 

now about the 1st of January, but 50,000 years hence, it will be 
in its perihelion in July, or time of mid-summer in the northern 
hemisphere, and at that time the earth's axis will be inclined 
nearly as at present, unless changed by some great convulsion, 
The effect of this change of the direction of the line of apsides 
will be therefore, to cause the earth to arrive at its perihelion at 
the time of mid-summer in the northern hemisphere, instead of 
at mid-winter as at present, thus producing, if the relative distri-y 
bution of land and water remains unchanged, a tropical climate 
or nearly so, over the whole globe. 

Such periods of time are however, too remote to be worth much 
notice from us, except for their interest in a geological point of 
view, for we believe this to be the true explanation of the greater 
warmth of the climate of the ancient world, as indicated by fossil 
flora and fauna ; we shall refer to this again. 

We have given no explanation of the cause of the precession 
of the equinoxes, or the motion of the apsides. It would be 
extremely difficult for us to do so in a manner intelligible to the 
general reader. The facts, however, are unquestionable. The 
former is caused by the attractions of the sun and moon upon the 
excess of matter at the equator, for the earth is not truly spherical, 
but oblate, on account of its diurnal rotation. This equatorial 
belt, not corresponding with the plane of the ecliptic, is acted upon 
obliquely, and with varying force by the sun and moon, producing 
the retro gradation of the nodes. The motion of the apsides is the 
conjoint effect of the attractions of the planets upon the earth in 
the various parts of its orbit. 

We here close the first part of our volume, not however, with- 
out the hope that we have succeeded in making it interesting^ 
and that the reader will feel repaid for the time spent in peru- 
sing it. 












THE WORLD. 



PART II 



METEOROLOGY. 



CHAPTER I. 

Meteorology. 

'• 'Tis pleasant, by the cheerful hearth, to hear 
Of tempests, and the dangers of the deep, 
And pause at times, and feel that we are safe ; 
Then listen to the perilous tale again, 
And with an eager and suspended soul, 
Woo terror to delight us." Southey. 

We now enter upon that part of our subject which treats of the 
atmosphere, the waters of the globe, and the mountain rocks of 
which it is composed. No department of natural history abounds 
mere in important facts and interesting conclusions. We com- 
mence first with " Meteorology." 

The science of meteorology describes and explains the various 
phenomena which occur in the region of our atmosphere. The 
word is of Greek origin and means aloft or elevated. It is a study 
which has deeply engaged the attention of men in every stage 
of society, from the roving savage to the refined votary of wealth 
and pleasure. The moment we cross our thresholds we commit 
ourselves to the influence of the weather ; but the hardier class 
of the community, the shepherd, the plowman, and the mariner, 
whose labor creates or procures the staple articles of life, are al- 
ways exposed by their occupation to the mercy of the elements 
They are hence led by the strongest motives, to examine closely 



116 THE WORL&. 

the varying appearance of the sky, and to distinguish certain mi- 
nute alterations which usually precede the more important chan- 
ges. Thus Virgil in one of the most beautiful passages of the 
Georgics gives for, the use of the mariner and husbandman, the 
warnings which in his time were thought to precede approaching 
storms of wind, which he observes, well contemplating, the care- 
ful husbandman will gather ^iis herds into their stalls; they are 
eleven in number* L The agitation of the sea, the swelling 
waves rolling upon the shore. II. Noise from the mountains of 
the rustling leaves and crackling branches* III. The roaring 
of the surf as it breaks upon the sjiore. IV. The murmuring of 
the groves. V. The flight of sea-birds and their screams. VL 
Their playing or sporting on the shore. VII* The herons forsa- 
king their accustomed marshes and mounting aloft. VIII. The 
fall of meteors, portending winds, and which is thus similarly al- 
luded to by Milton : 

" Swift as a shooting star, 
In Autumn thwarts the night, when vapors fired 
Impress the air; and show the mariner 
From what point of his compass to beware 
Impetuous winds." 

IX. Nocturnal streams of light, probably the Aurora. X. Straws 
rising and floating in the air. XI. The play of floating feathers 
driven about upon the surface of the pool. Next he gives twelve 
prognostics of rain, which were thought so conclusive in their 
indications that he observes "Never hath a shower hurt any per- 
son unforewarned, ,, viz: thunder from the north; the clash of east 
and west winds, and the flight of the cranes into the vallies to 
avoid the impending tempests. Heifers snuffing the wind; the 
circling flight of swallows round the water, and skimming over 
its surface. The croaking of the frogs; ants busy with their eggs* 
The rainbow, which was then supposed to have drank the water 
that supplied the clouds. The hoarse murmur of the flocks of 
crows. The diving of sea birds and of swans; smoothing and 
oiling their plumage. A solitary bird pacing the sand; and lastly 
the gathering of fungous excrescence on the wick of the lamp,, 
causing the oil to sputter and the flame to emit sparks. Prognos- 
tics of the coming weather drawn from the appearance of the 



INDICATIONS OF THE WEATHER. 117 

moon or sun, are also given. I. From the moon; darkened when 
new, she betokens rain. If red, wind: if serene in the fourth 
night she promises fair weather for that month. II. From the 
sun; if in rising, spotted, or showing only the centre of his orb, 
rain is portended. If of a bluish color in setting, rain, if red., 
wind. If spotted at setting, rain and wind; and if bright at ris- 
ing and setting, clear weather with a northerly wind. 

After these beautiful descriptions, which bring the poem home 
to every one, follow nine indications of fair weather. The bri ght- 
nes of the stars, and of the rising moon. The unclouded sky, 
and kingfishers not expanding their wings to the sun; sows no 
longer tossing wisps of straws into the air. The clouds floating 
low; the silence of the owl at sunset, whose hooting was once 
supposed to forebode rain. The falcon soaring after the lark, and 
the crows social, and cawing with clear notes. Many of these 
signs are even now considered as harbingers of the coming change 
of weather, and more particularly the formation and arrangement 
of certain clouds, to which we shall again allude. No doubt the 
early observers of the weather often mistook the indications of 
those aspects we have mentioned, and inferred conclusions from 
mere casual circumstances. 

The signs which usually precede the coming tempest are thus 
beautifully given by Thorns on.—, (Winter, I. 118, et seq.) 

" When from the pallid sky the sun descends, 
With many a spot, that o'er his glaring orb 
Uncertain wanders, stain'd — red fiery streaks 
Begin to flush around. The reeling clouds 
Stagger with dizzy poise, as doubting yet 
Which master to obey ; while rising slow, 
Blank, in the leaden-colored east, the moon 
Wears a wan circle round her blunted horns. 
Seen through the turbid, fluctuating air 
The stars obtuse emit a shivering ray ; 
Or frequent seem to shoot athwart the gloom, 
And long behind them trail the whitening blaze. 
Snatch'd in short eddies, plays the wither'd leaf; 
And on the flood the dancing feather floats. 
With broadeird nostrils to the sky upturn'd 
The conscious heifer snuffs the stormy gale. 
Even as the matron, at her nightly task. 



118 



THE WORLD. 



With pensive labor draws the flaxen thread, 
The wasted taper and the crackling flame 
Foretell the blast. But chief the plumy race, 
The tenants of the sky, its changes speak. 
Retiring from the downs, where all daylong 
They pick'd their scanty fare, a blackening train 
Of clamorous rooks thick-urge their weary flight, 
And seek the closing shelter of the grove. 
Assiduous, in his bower, the wailing owl 
Plies his sad song. The cormorant on high 
Wheels from the deep, and screams along the land. 
Loud shrieks the soaring hern ; and with wild wing 




The circling sea-fowl cleave the flaky clouds. 

Ocean, unequal press'd, with broken tide 

And blind commotion heaves ; while from the shore. 

Eat into caverns by the restless wave, 

And forest-rustling mountain, comes a voice, 

That solemn-sounding bids the world prepare. 

Then issues forth the storm with sudden burst, 

And hurls the whole precipitated air 

Down in a torrent." 

Those tokens which portend the more violent convulsions of 
the atmosphere, the pelting storm, or the careering tempest, are 
generally of a decided character, but the symptoms which go 
before the ordinary fluctuations of the weather can only be dimly 
conjectured by long experience and sagacious observation. 

Nothing can be more utterly groundless than the disposition to 
refer the ordinary changes of the weather to the influence of the 
moon. But, compared with this, the fancied efficacy of the stel- 
lar aspects vanishes into the shadow of a vision. The moon by 






BAROMETER. 119 

its attraction does raise a small tidal wave in the atmosphere, 
which is indicated by the barometer, but its effect is scarcely per- 
ceptible. According to the calculations of Laplace, the joint ac- 
tion of the sun and moon is only capable of producing a tropical 
wind flowing westward at the rate of about four miles a day, and 
the effect produced by the 'conjoint actions of Jupiter and Venus, 
when nearest the earth, would be a very gentle breeze moving 
about a foot in fourteen or fifteen days, or about a mile in twenty 
years. 

The invisible and perfectly elastic fluid which surrounds the 
earth is called the atmosphere, or atmospheric air. It appears to 
consist principally of two distinct expansible fluids, mechanically 
combined in different proportions, a single portion or atom of oxy- 
gen gas being united to three parts by weight, or four by bulk of 
nitrogen, with a very slight admixture of carbonic acid, perhaps 
one-thousandth part of the whole. Air was formerly considered 
as an elementary body, but the analysis of this rare medium is 
one of the finest discoveries of chemistry. The atmosphere, al- 
though apparently so rare and mobile, is nevertheless, capable of 
presenting great resistance to any obstacles to which it may be 
opposed. We shall see this more completely illustrated when we 
describe the phenomena attending hurricanes and other windy 
storms, but meanwhile it will answer our present purpose to simply 
refer to its use as a natural agent in propelling vessels by means 
of sails, and urging the sails of wind mills. Although it is, com- 
paratively speaking, light, and in the ordinary acceptation with- 
out weight, yet we must not forget that it is now clearly demon- 
stratable that the atmosphere which invests our earth, presses 
everywhere on its surface with a power of about 15 lbs. to the 
square inch. The famous Torricellian experiment proves this. 
It is well known that if the mouth is applied at one end of a small 
tube, the other end of Which is immersed in water, that upon ex- 
hausting the air from the tube by the process called suction, 
the fluid rises swiftly and flows into the mouth; this is a philo- 
sophical experiment, but well known to every child. Now, if a 
person ignorant of the principle that caused the water to rise in 
the tube, should be asked for an explanation, he might answer 



120 THE WORLD. 

as Galileo did, that it was " Nature's abhorrence of a va- 
cuum." It is however, effected by the pressure of the atmosphere. 
When an open tube is dipped at one end into the water, the li- 
quid does not rise in the tube until the air within it is removed by 
exhaustion, as we have described, when immediately the fluid 
rises, because the atmosphere without the tube, pressing upon the 
mobile particles of the fluid, forces them up. Now it is evident 
that if the tube was long enough, and the exhaustion perfect, the 
pressure of the air upon the liquid outside would raise a column 
of water just so high that the weight of this elevated water would 
be equal to the pressure of the atmosphere upon the liquid at the 
bore or orifice of the tube. The column of water which can be 
thus raised or sustained, is generally about 33 feet high; and as 
such a column when its area is one square inch, weighs about 15 
pounds, we infer that the atmosphere presses upon the earth with 
a force of about 15 pounds to the square inch. • Mercury or quick- 
silver, being 14 times heavier than water, the atmosphere will 
support a column of this but about 29 or 30 inches in height; and 
when a tube a little more than 30 inches long is closed at one end, 
and filled with mercury, and then inverted into a basin also con- 
taining mercury, the column will remain suspended nearly thirty 
inches high. The mercurial column would continually remain at 
the same elevation, if the atmosphere was subject to no variations; 
but this is not the case; upon observation it is found subject to 
continual variation, almost always falling before a wind arises, 
and preceding rain, and again rising at the approach of calm 
and fair weather. The. instrument thus becomes a barometer, or 
measurer of of the weight of the air. It is an invaluable instru- 
ment on ship-board, giving indications of the coming tempest 
long before any change is detected in the appearance of the sky. 
Since the barometric column is wholly supported by the press- 
ure of the atmosphere, communicated through the mobile parti- 
cles of the fluid metal, to the open mouth of the tube, it obvious- 
ly points out a method of determining heights. This however, is 
from several causes, a matter of some nicety ; thus the density 
of the air decreases as we rise upward, owing to the extreme 
elasticity of air. It is well known that a piston may be thrust 



DENSITY OF THE AIR. 121 

down a tube closed at one end, condensing the air before it, until 
it can absolutely be urged no farther, the included air resisting its 
descent as effectually as any metal ; upon releasing the pressure 
it again expands to its original bulk. The stratum of atmosphere 
in immediate contact with the earth is subject to the entire press- 
ure of the superincumbent mass, and is thus denser, i. e. has 
more atoms contained in the same space than the stratum imme- 
diately above, and the second stratum is denser than the third, 
and so on. This decrease of density gives a limtt to the extent of 
the atmosphere. 

The ancients imagined that our atmosphere reached at least as 
far as the moon, but the discover}' of the weight and pressure of 
the air destroyed at once this magnificent vision. Comparing 
the length of the mercurial column with the density of the aerial 
medium, it follows that if the atmosphere is a uniform fluid, it 
cannot exceed the elevation of live miles. But the air being 
very dilatable, the higher por'tions sustaining as we have shown 
a diminished pressure, must swell upwards and occupy a propor- 
tionally greater space. This property removes the boundary of the 
atmosphere to a much greater elevation. A height of 42 miles 
would indicate a rarefaction of a thousand times, for it has been 
proved that the density decreases in a geometrical ratio, as the 
height increases in an arithmetical ratio, thus : 



The elevation being in miles, 


|0|3|6|9| 19 | 15 l&c. 


The density will be, 


|l|i|||J|l-16|l-32|&c. 



The famous Kepler first proposed a method of determining the 
height of the atmosphere by means of the twilight. After sunset 
there appears in the western sky a bright illumination called twi- 
light, which is caused by the sun's rays shining upon the higher 
regions of the air. This twilight fades when the sun has sunk 
below the horizon a certain distance ; thus, let C be the position 
of a spectator upon the earth, encompassed with its atmosphere, 
and SAB the lowest ray of the sun after sunset, B C being the 
horizon, The sun's rays would now illluminate the portion of 
atmosphere between A and B, producing twilight visible to a spec- 
tator at D, but not to one at C. Now T the twilight, or this last ray 



122 THE WORLD. 

of twilight, SAB, expires whenever the arc DC, is equal to 9°, 




or one-fortieth of the whole circle. The angle B C O is evident- 
ly a right angle, or 90°, consequently, from the well known prin- 
ciple that the square of the longest side of any right angled tri- 
angle, as B O C, is equal to the sum of the squares of the other 
two sides; the square of B O, is equal to the square of O C, ad- 
ded to the square of B C. Now B'O is the height of the atmos- 
phere, added to the half diameter of the earth, and O C is also 
the semi-diameter of the earth, or 4000 miles nearly, whilst B C, 
which may be assumed equal to D C, is the one-fortieth of the 
circumference of the earth, or 600 miles nearly. Hence the square 
of B O is equal to 600 2 , plus 4000' 2 , which is 16,360,000, and the 
square root of this is 4045, which is the length of B O; subtracting 
D O, or 4000 miles, leaves 45 miles for B D, the height of the 
atmosphere. It is probable the atmosphere extends be}'ond this, 
as, unless the sky be overcast, there is total darkness in no climate, 
even at midnight, and therefore the atmosphere must extend to 
such a distance as to receive -the most dilute glimmer after the 
sun has attained his greatest obliquity, and sunk 90° below the 
horizon ; this would require an elevation of at least 1640 miles, 
and before the centrifugal force would balance the attraction of 
gravitation, it is possible it might extend 22,000 miles, and yet, 
this is scarcely a twentieth part of the distance of the moon. If 
the atmosphere really spreads out, even to the first mentioned 
1 imit, it must, in its remote verge, attain a degree of tenuity which 
it would bafrle the imagination to conceive. 

It was soon conceived, after the discovery of the pressure of 
the air, that the height of the mercurial column would vary with 



PRESSURE OF THE AIR. 



123 



the elevation at which it was observed. The experiment was 
tried by M. Perier, at the suggestion of his brother-in-law the 
celebrated Pascal, who himself living at Paris, was not so con- 
veniently situated as M. Perier, who lived at Clermont, in Au- 
vergne, in the immediate vicinity of several mountains, which 
modern geology proves to have once been active volcanoes. Early 
in the morning of the 19th of September 1648, (two hundred 
years ago) Perier with a few friends, assembled in the garden of 
a Monastery situated near the lowest part of the city of Clermont, 
where he had brought a quantity of mercury, and two glass tubes 
closely sealed at the top. He filled and watched them as usual, 
and found the mercury to stand in both tubes at the same heigh^ 
namely 28 English inches; leaving one behind in the custo4y of 
the sub-prior, he proceeded with the other to the summit of the 
mountain, the Puy de Dome, and repeated the experiment. Here 
the party were delighted, perhaps we may say surprised, although 
they expected it, to see the mercury sink more than three inches 
under the former mark, and remain suspended ^.t a height of 
only 24.7 inches. In his descent from the mountain he ob- 
served at two several stations, that the mercury successively rose, 
and returning to the monastery it stood at exactly thes;ime point 
as at first, thus incontrovertably proving that it was the pressure 
of the atmosphere which balanced the suspended column. 

We will close this chapter with a description of a barometer or 
baroscope, which any one who has access to a tin -shop can 




construct, it is an instrument of great delicacy in its indications. 
Let A B C D, be a vessel partly filled with water, in which the 



124 THE WORLD. 

hollow air-tight body a b c d is floating, having a tube, ef, opening 
into the interior. When placed into the water it is evident that 
a certain portion of the liquid will rise in the tube, and if light 
weights are added either below or above, the whole body may be 
caused to sink until its top is even with the surface of the fluid ; 
ag is likewise a tube, which containing air, will prevent the in- 
strument in great changes of weather from sinking to the bottom, 
b h, is a wire, and g h and i b are threads stretched obliquely from 
the tube to the wire. As the instrument rises and falls, a little 
bubble of air on the thread shows the motion; the threads are so 
located that when the bubble reaches i on the lower, it commences 
at k on the upper one. A change of the pressure of the atmos- 
phere preceding a wind or rain, by reason of a diminished press- 
ure upon the surface of the water in the vessel, A B C D, forces 
less of the fluid into the tube cf, and thus the specific gravity of 
the included air being lessened by its expansion, the instrument 
rises, and the bubble descends, corresponding with the fall of the 
mercury in the barometer. When, on the approach of fine weath- 
er, the atmosphere becomes calm, and of its usual density and 
elevation, the water being forced into the tube ef, by the increased 
pressure causes the baroscope to sink, and consequently the bub- 
ble to rise. It is said that this instrument will show alterations in 
the air 1200 times more accurately than the common barometer. 
The inventor, Mr. Caswell of Oxford, observes that the bubble 
is seldom known to stand still even for a minute ; that a small 
blast of wind that cannot be heard in a chamber will sensibly 
make it sink, and that a cloud passing over it always makes it de- 
scend. The greatest objection to this very simple instrument is, 
it is liable to be affected by the expansion of the included air by 
heat. 



125 



CHAPTER II. 

Winds. 

** He spoke, and, at his call, a mighty Wind, 
Not like the fitful blast, with fury blind, 
But deep, majestic, in its destined course, 
Sprung with unerring, unrelenting force, 
From the bright East. Tides duly ebbed and flowed; 
Stars rose and set; and new hoiizons glowed; 
Yet still it blew. ' ' Rogers, 

In the preceding chapter we have alluded to the weight and 
decreasing density of the air. In the present we shall consider 
it in its relations to heat and moisture, in which connection it per- 
forms a most important part in the economy of nature. Air, like 
all material bodies, expands when heated, and thus its specific 
gravity being lessened, it rises. Every one is familiar with this 
fact. The little whirligigs placed on stoves, are turned by the 
ascent of the heated air, and the draft of chimneys and pipes de- 
pends upon the same principle. We might infer that if air ex- 
pands upon being heated, it will part with this heat on being con- 
densed. This is the fact, upon forcing a close fitting piston down 
a tight tube, suddenly compressing the air before it, a heat is 
evolved, sufficient to inflame good tinder. We well remember 
in our younger days performing this feat, using a leaden tube for 
the pipe, and a bit of wood with a circular and greased leather 
nailed to one end, for a piston, placing the "punk" in the folds 
of the leather. 

The ascent of heated air from the earth is one of those silent 
and often unobserved agencies employed to produce a general 
equilibrium in the temperature and moisture of the earth. The 
air itself being transparent, is scarcely heated by the passage of 
the suns rays, but the stratum nearest the earth absorbing a por- 
tion of the heat, rises and gives place to a colder portion, which 
in its turn is displaced by another, and thus the excessive heat 
which, in some portions of our globe, would parch up the earth 
and destroy all life, is rapidly carried off, and a more genial tern- 



126 



THE WORLD. 



perature produced. The heated portions of air distribute their 
warmth throughout the great body of the atmosphere, and -some- 
times in the form of winds sweeping over colder regions of the 
earth, moderate the rigor of the climate. 

Ascending from the earth we find the temperature of the air 
constantly diminishes until we arrive at a region of frost, the 
limit of which, is called the term of perpetual congelation. The 
height of the term of congelation varies for every change of 
latitude. In the following diagram taking A B, for the height of 




B 



80° C 



perpetual congelation at the equator, and B C, for the line of lati 
tudes, then the decrease in the height of the term of congelation 
from the equator to the poles, ma} r be represented by the several 
parallels bounded by the curved line A C. The region of per- 
petual frost at the equator is at a height of 3 miles, at a distance 
of 35° from the equator, about 2 miles, at 54° about 1 mile, at 
80° very near the surface of the earth, and at 90° the surface of 
the earth. It will be well to fix in the mind, the limits here as- 
signed, as we shall often refer to this varying elevation in explain- 
ing the phenomena of rain, hail and snow. The clouds almost 
always float below the term of congelation. 

Although the temperature of the surrounding atmosphere is 



TEMPERATURE OF TALLEYS. 127 

generally colder as we ascend, yet from local circumstances the 
heat of the earth being increased, the air becomes sometimes 
very mild even in elevated districts. Valleys, it is well known, are 
warmer than level plains in the same latitude on account of the 
reflection of the sun's heat from neighboring hills and mountains. 
In Switzerland, instances occur of spots of verdure in the midst 
of perpetual snow and glaciers. We give below a view of the 
glacier- of Grindelwald in the Canton of Berne. Here woods 
and meadows border close upon the immense fields of ice, which 




descending from the upper regions, cover an extent of about 1500 
square miles of territory. The ice is seen presenting innumer- 
able peaks in the gorge between the mountains. It is said that 
there are plains in the Himalayan mountains 15,000 feet above 
the level of the sea which produce fine pasturages. 

Air when put in motion produces what is called wind, and the 
variable distribution of heat throughout the atmosphere is the 
main cause of wind, or rlow of the air, for thus the local density 
is constantly affected, and the equilibrium of the mass disturbed. 
Winds are exhibited in various forms, breezes, high winds, gales, 
hurricanes and tornadoes. These varieties depend chiefly upon 
their different velocities, a velocity of twelve miles an hour mak- 
ing a strong breeze: sixty miles, a high wind: one hundivd miles 
a hurricane. 

The force of the wind when moving witfa the velocity of a 
hurricane or tornado, is almost incredible : when we speak of ihe 
geological changes that have passed over the face of our globe 



128 THE WORLD. 

during its past existence, we shall have occasion to refer to their 
agency ; no power can resist the combined action of winds and 
waves. Hurricanes and high winds are generally characterized by 
a whirling motion producing the phenomena called whirlwinds, 
these often exhibit the most incredible power, uprooting huge 
trees, and whirling their dismembered fragments into the air, 
unroofing houses, and even raising aloft animals, and heavy carts. 
The great gales of the ocean manifestly exhibit more or less of 
this rotary motion. Such are the the hurricanes which annually 
sweep over the Indian seas and along the Atlantic coast. 

Our limits will not permit us to be very extended upon this sub- 
ject, and we shall therefore briefly notice some of the more pecu- 
liar winds, and we commence with the land and sea breezes. 
These are occasionally met with in every latitude, but are con- 
stantly observed near the shores of the continent, and of the lar- 
ger islands within the tropics. In these sultry regions, as the 
day advances, a refreshing wind blows from the sea, and is suc- 
ceeded by an opposite current from the interior of the land on the 
approach of evening. The cause of these diurnal winds is obvi- 
ous. The change of temperature between the night and day on 
land often varies more than 40° or 50° Fahr., while at the same 
time on the water it seldom varies more than 1° or 2°. The 
large body of heated air over the land, rising continually during 
the day, a denser and colder portion rushes in from over the wa- 
ter to supply its place, causing the sea breeze. During the night 
the ground cools much more rapidly than the water, and the lower 
stratum of atmosphere thus soon becomes colder than at sea, 
consequently a stream of air thus flows toward the sea, displacing 
the lighter and warmer air, producing the land breeze. This breeze 
is never as powerful as the sea breeze, but is much colder. Every 
one who is familiar with these breezes must have noticed the pe- 
' riod of peculiar languor and depression, between the change from 
the sea to the land breeze. 

Dr. Robinson mentions an experiment which illustrates the 
cause of land and «ea breezes very prettily. If we place a hot 
stone in a room, and hold near it a candle just extinguished, we 
wilUsee the smoke move toward the stone, and then ascend up 



TRADE wwnrn 129 

from it, precisely similar to the movement of the air, heated by 
contact with the land, and perhaps the sloping sides of moun- 
tains. The most remarkable aerial currents, and of the greatest 
importance in navigation, are the trade winds, which, within the 
tropics, blow continually from the east, though with variable force, 
and declining north and south, according to the latitude, and sea- 
son of the year. The primary cause of the trade winds is anala- 
gous to that of the land and sea breezes, though much more ex- 
tensive, and maintaining a constant direction, and likewise united 
with the influence of another cause, viz : the rotation of the 
earth. We have already had occasion to remark that within the 
two tropics lies a belt, over some part of which the sun is verti- 
cal at noon, at all seasons of the year, hence this equatorial belt, 
in the torrid zone, is continually heated by the sun, and a large 
body of air warmed by contact with the heated ground, rises con- 
stantly to the upper regions. Its place is supplied by colder air 
moving along the surface of the earth, from the colder northern 
and southern climates. The effect of this w r ould be to produce 
a north wind north of the equator, and a south wind south of the 
equator. The portion of air thus transferred from the higher lati- 
tudes to the equator has a slower diurnal motion than at the equa- 
torial regions. Perhaps a diagram will make this more plain. 




Let P be one of the poles of the earth, A B a parallel of latitude, 
and E E, the equator. Now it is evident that the diurnal move- 
ment of a body attached ,to the parallel A B, is slower than one 
at the equator E E, since the equatorial belt or circle, is of much 
greater circumference than the circle of latitude, and both are 



130 THE WORLD. 

moved over in the same time. If therefore, a body, still retain- 
ing the quantity of motion it had while upon A B, should sud- 
denly be placed upon E E, it is evident that the excess of motion 
at E E would leave it behind. This is actually the case with the 
colder air rushing from the higher latitudes to fill the space vaca- 
ted by the ascent of heated air within the tropics. The air thus 
transferred, does not acquire at once the motion of the equatorial 
regions, and consequently lags behind, or the earth moves under 
it, and thus since the earth moves from west to east upon its axis* 
it gives the appearance of a wind coming from the opposite quar- 
ter, i. e. from the eastward. But, as we have seen before, these 
winds had a direction from the north , at all places north of the 
equator, and from the south, at all places south of the equator* 
combining the two therefore, we will have a constant north-east 
wind one side of the equator, and south-east the other; these two 
winds, meeting at the equator, will flow constantly eastward, or 
destroy each other and produce a calm. Such is the character of 
that general wind, which encircles the globe, flowing with slight 
deviations, constantly from the east, and spreading over a zone of 
more than 50° in breadth. It sweeps the Atlantic ocean from the 
coast of Africa to Brazil, and the Pacific from Panama to the 
Phillipine islands, and New Holland; and again over the Indian 
sea partially, from Summatra to Zanguebar ; here however its 
direction is curiously varied, owing to the peculiar locality of this 
ocean. 

The course of the trade winds is changed or interrupted by high 
lands, thus calms and variable winds prevail at the Cape Verd 
islands, being under the the lee of the African shore, and an eddy, 
or counter current of air from the south-west, ife generated under 
the coast of Guinea. The lofty barrier of the Andes shelters 
the sea on the Peruvian shores from the trade winds, which are 
not felt until a ship has sailed eighty leagues westward, but the 
intervening space is occupied by a wind from the south. The 
heated air of the tropics after becoming somewhat cooler in its 
passage towards the temperate regions, descends to the earth 
still retaining in a great measure, its equatorial velocity, conse- 
quently, it sweeps over the surface of the earth in the same di- 



UOKSOOB6. 131 

rection in which it is turning, but somewhat faster; this gives the 
appearance of a westerly wind of considerable force and regular- 
ity. According to Robbins, a westerly wind almost constantly 
prevails in abouL latitude 60° S. in the Pacific ocean. In Hud- 
son's Bay, westerly winds prevail three-fourths of the year, as also 
in Kamschatka. Still farther north, as at Melville island, the 
north, and north-west winds prevail. On account of these winds, 
the Atlantic may be crossed eastward in about half the time of 
returning westward. The existence of the upper current of the 
trade winds was shown in a striking manner at the eruptions of 
the volcano in the island of St. Vincent in 1812. The trade 
winds blow with great force from Barbadoes to St. Vincent, but 
ashes erupted by the volcano fell in profusion from a great height 
upon Barbadoes, which is about 150 miles westward. Since the 
westerly winds which prevail in the higher latitudes are caused 
by bodies of air from the torrid zone, which often descend to the 
earth before the heat is quite gone, such winds are generally 
warm, and on the same principle winds w T hich blow directly from 
the arctic pole, are intensely cold, and, as they must appear 
from the rotation of the earth, to come from the north-east, our 
easterly and north-easterly winds are always severely cold. 

We will now consider the causes which result in changing the 
direction of the trade winds in the Indian ocean, producing what 
are termed the monsoons. When it is summer in the northern 
hemisphere the great body of land above the Indian ocean be- 
coming more heated than the sea, a breeze sets towards the land, 
which, modified by the rotation of the earth, gives a strong south- 
east wind. On the contrary, when it is winter in the northern 
latitudes, the great body of water, as also the vast island of New 
Holland, becoming more heated than the continent farther north, 
a wind sweeps over the Indian and southern oceans, whose 
general direction is south-west ; this wind not being opposed in 
direction to the rotation of the earth, is more powerful than the 
other. The interval which separates the monsoons is varia- 
ble, but occurs generally near the equinoxes, during this interval, 
violent gales occur called Typhoons. 

According to Mr. Redfield, who has most ably and successfully 



132 THE WORLD. 

investigated the phenomena of the great storms which traverse 
the Atlantic coast, they may be traced to the N. E. of the West 
India islands, and are from thence, drifted to the westward on a 
track which inclines generally to the northward and eastward. 
The rate of progression varies from 12 to 30 miles per hour, and 
the storm whirls or blows from right to left, in a horizontal circuit, 
on a vertical and some what inclined axis of rotation which is 
carried forward by the storm. Mr. Espy has proposed a theory 
which to us appears at variance with the facts derived from gen- 
eral observation, and independent of any hypothesis. According 
to this doctrine, it is alleged that during hurricanes, the wind, in- 
stead of blowing in a circle, rushes directly from the exterior to- 
wards the centre, to supply a vertical current under influence of 
the suction, or vacuum power caused by the rarefaction and as- 
cent of air, consequent from the extrication of the latent heat of 
vapor during condensation. This theory has been ably defended 
by Dr. Hare. The rotary theory of storms is now pretty generally 
acknowledged, and has been advocated by Mr. Redfield, Sir 
John Herschel, Lieut. Col. Reid, Prof. Dove of Prussia, and 
Mr. Alex. Thorn. The latter gentleman has published a book 
on the nature and course of storms, in which, he traces the ori- 
gin, and describes the phenomena, of the great hurricanes annu- 
ally occurring in the Indian ocean, showing them to be vast cir- 
cuits of wind, revolving in a particular direction with unerring 
regularity ; that they move from about latitude 10° S. by a south- 
westerly track, curving towards the tropic. Their diurnal rate of 
progression diminishes as they recede from the equator. These 
hurricanes are formed by the westerly monsoons, and the S. E. 
trade winds; the following diagram is extracted from Mr. Thorns' 
work, and will illustrate the manner in which these storms are 
generated. 

When the hurricanes are first noticed they are from 400 to 
500 and even 600 miles in extent, or diameter, and consequently, 
as the space between the monsoons and the trades is seldom 
more than 100 miles, the outer portions of the circle must be in- 
volved in the two winds for the space of two hundred miles on 
each side. Each wind therefore communicates a part, if not the 



HURRICANES. 133 

whole of its motion, in a tangential direction, and by their reverse 
•directions produce a uniform circular motion. If the south-east 



y. E. Trades. 
^> ^ ^ 



of « 




Westerly Monsoons, 
trade impinges upon one side at the rate of 30 miles per hour, 
aud the monsoon at the same velocity on the other, the amount, 
converted into a rotary motion, would be equal to GO mifefl at the 
exterior. The stormy revolution appears to extend to a great 
height, passing over the lofty mountains of the Isle of Bourbon 
and the Mauritius without being destroyed, though these arrest the 
trade winds. The same cause which produce- t lie gyratory mo- 
tion carries the storm forward. 

The awful phenomena developed during a hurricane, depend 
upon the sudden reductions of the masses of air involved in it, 
of different temperatures, to the same standard, producing the 
most terrific exhibitions of thunder and lightning, attended with 
rain, hail &c. The trade winds are cool, but the monsoons are 
hot and humid. In most hurricanes, the fall of the mercurial 
column is equal to 1 inch, or even 2 inches, and the velocity of 
the wind just entering the focus as great as 150 miles an hour. 
In the focus of a rotary storm the horizontal direction of the wind 
suddenly ceases, and often, the storm appears, to one ignorant of 
its nature, to have passsed off, when suddenly it commences again 
with the utmost fury, and at a point of the compass opposite to 
where it left off. This fact is strikingly noticeable even in the 
small hurricanes which in the autumn and spring, blow over our 
western lakes, and we have several times witnessed a violent 
hail and thunder storm, during which the wind raged with the 

G 



134 



THE WORLD. 



utmost fury, to apparently rettirn with the wind in quite the op- 
posite direction, after an interval of 15 or 20 minute? of perfect 
calm. The cause of these calms and the course of the air in the 
focus of a circular storm, is represented in the diagram. 




We have scarcely room to -add a description of the famous 
Rodriguez hurricane of April 1843. Such a fleet of wrecks from 
one storm never was seen before, having 14 or 15 vessels entan- 
gled its stormy circuit, some on its skirts, others crossing its path 
and following its wake, some rushing into the very focus and scud- 
ding around the vortex till rendered perfectly unmanageable by 
the fury of the sea and wind ; its course could be tracked for 
3500 miles, demonstrating beyond a doubt, that it was a vast 
whirlwind. We give a diagram of its position on the 4th of April, 
when* its centre had just passed over the island of Rodriguez. 
Tile arrows represent the positions of the vessels and the direc- 
tion of the wind, as gathered from the log-books. Though some 
of these vessels were but a few hundred miles from each other, 
yet they had the wind from opposite quarters. 

Besides the winds which we have mentioned we may enumerate 
among local winds, or winds which affect only particular sections 
of country, the Sirrocco, a hot wind, moist and relaxing, which 
visits Naples and the south of Italy, blowing from the opposite 
shores of the Mediteranean. This wind is very unhealthy; during 
its continuance all nature seems to languish, the vogetation droops 
and dies, and the animal spirits are too much exhausted to per- 



VARIOUS WINDS. 135 

mit any exertion. The Harmattan is a cold dry wind of very 




parching quality, frequent in Africa; it is a periodical wind of un- 
certain continuance, and is attended by a thick fog or haze,which 
either wholly obscures the sun or makes it appear a faint red easily 
borne by the eye. It is so dry that the eyes, lips, palate &c, are 
parched and painful, causing the skin to shrink and cracjt, and 
sometimes to peel off. It is however considered as an effectual 
cure for some diseases. The Samiel or Simoon, is a burning, pes- 
tilential blast, extremely arid, which springs up at times in the 
vast deserts of Africa, and rushes with tremendous fury, involving 
whole pillars of sand. It produces instantaneous death, and 
mortifies the body so effectually, that the limbs may be separated 
without difficulty- The camels seem to have an almost instinctive 



136 THE WORLD. 

notice of its approach, and are so well aware of the noxious quali- 
ties arising from its extreme dryness, that they bury their noses 
in the sand to avoid breathing it. So impetuous is this wind that 
its fury is past in a few moments. 

We have now briefly described the more prominent winds 
which blow over the surface of our globe. We shall, when con- 
sidering the changes which have modified, or entirely altered the 
face of the various continents and islands, which at present, form 
the "dry land" of our planet, perceive that they have acted a 
most important part. No force can resist the perpetual assault of 
the winds and waves. The sea, lashed into fury by the careering 
tempest, forces its way through barriers of porphyry and granite, 
undermines the rocky cliffs, and piles immense dunes or sand- 
hills along the low shores. Beneath the fine sands of the bound- 
less eastern deserts, the monuments of ancient Egypt, her sta- 
tues and sculptured temples, have lain hidden for ages, but the 
dry impalpable powder has fallen harmless upon them, and now, 
when the curious traveler from the western world, from lands 
unknown to the hierophants, uncovers with careful hands the 
buried tombs of kings, he beholds the color glowing upon the 
walls as bright, and perfect, as when first laid on by the Egyptian 
artist 3000 years ago ; and the winged globe and heads of Isis 
as sharply outlined as though chiseled but yesterday. 



137 



CHAPTER III. 

Formation of Clouds and Dae 

" The clouds consign their treasures to the fields, 
And, softly shaking- on the dimpled pool 
Prelusive drops, let all their moisture flow 
In large effusion o'er the freshen'd world." 

Thomson. 

The relations of the atmosphere to water are very important 
and numerous. The various winds as they sweep over large 
tracts of country, or the ocean, become charged with moisture, 
which they bear with them to the higher regions, to be there em- 
ployed in the formation of clouds, or rain. The formation and 

4 

dissolution of clouds, produces all the varied train of meteoro- 
logical phenomena. The humidity suspended in the atmosphere 
is derived by exhalation partly from the land, but ultimately from 
the vast expanse of the ocean. The moisture, deposited by the 
air is in the form of minute globules, which remain suspended, or 
subside slowly, constituting a cloud. When it comes near us, 
whether it hovers on the tops of the hills, or spreads over the 
valleys, it receives the name of &fog; when deposited from the 
air in a clear night, upon the surface of the ground, or bodies ex- 
posed to the air, it is called dew. 

In order to explain more clearly the formation of clouds and 
also the deposition of dew, let us consider in what manner the 
capacity of air for moisture will be affected either by heat or cold. 
By capacity, we mean power of stowing away so as to render in- 
visible. As a general rule, we find the capacity of air for mois- 
ture increased by heating, and dimished by cooling, it being ca- 
pable of taking up and holding in an invisible state, a greater 
quantity of water when heated, than it can retain when cooled. 
Although the capacity of air for moisture is increased by heating, 
yet it is not proportional to the heat, but increases in a faster ratio. 



138 THE WORLD. 

For instance, an increase of temperature 10°, of air already heated 
to 70°, will increase its capacity for water much more than the 
same increase to air heated to only 40°. The converse of this 
is also true, the cooling of hot air diminishes its capacity for heat, 
much faster than the cooling of air already cold. Air in mount- 
ing upwards becomes colder, and since every increase of cold is 
attended with a dimunition of capacity for moisture, it becomes 
proportionally damper, and thus the middle regions of the atmos- 
phere become soon charged with moisture, and were it not for a 
conservative principle which we will now mention, the heavens 
would be perpetually shrouded with clouds ; this principle is, air 
in expanding has its capacity for moisture increased, and there- 
fore, as the air which is ascending, continually expands from the 
dimunition of pressure, it becomes consequently drier and drier. 

Clouds are formed either by a watery vapor rising so high as to 
reach a degree of cold sufficient to condense it, or from a mix- 
ture of warm air with cold, the moisture being derived from the 
warmer portion. Fog is nothing more than a cloud formed upon, 
or near to, the surface of the earth, and is due to a mixture of 
warm and cold air. Thus in a cold morning we see moisture 
deposited from the warm breath of animals, when it comes in 
contact with the air. The course of that remarkable body of wa- 
ter which is called the Gulf Stream, and which flows in a warm 
current from the Gulf of Mexico as far up as the banks of New- 
foundland, is marked by a fog, produced by the colder air sweep- 
ing over it. Fogs are not common in hot climates, the air being 
too warm near the surface of the earth to condense the moisture 
sufficiently to form a cloud. 

Dew is formed when air charged with moisture comes in con- 
tact with a surface in a certain degree colder than itself. The 
formation of dew may be very prettily illustrated by bringing a 
tumbler of cold water into a warm room, the outside of the tum- 
bler will soon be covered with a coat of moisture, deposited from 
the warm air which has come in contact with it. In order to 
have a copious deposite of dew it is essential that the ground 
should be considerably colder than the air above it t and, it is act- 
ually found, that upon those nights when the most»copious dews 



DBW. 139 

occur, the ground becomes 12 or 15° colder than the air a few 
feet above it. Dew is deposited very unequally upon various 
substances; plants and vegetables, which need this sustenance, 
receiving the greatest abundance ; but little is deposited upon the 
dry land, still less upon polished metalic bodies, and none at nil 
upon the ocean. The deposition in these cases is proportional lo 
the temperature, some bodies growing much colder than others 
when exposed to the same cooling influence ; the surface of the 
ocean, as we have before remarked, remains at nearly the same 
temperature as tho air incumbent upon it. 

The surface of the earth is cooled by radiation of the heat it 
has received during the day, and thus prepared for the deposition 
of the dew. Hence dews are most abundant in a slear night 
when the heat radiated from the earth is not intercepted and 
thrown back from overhanging clouds. It is from this circum- 
stance that the vulgar notion arises that the rays of the moon 
have a chilling influence. When the ground becomes cooled by 
the radiation of heat from its surface, below 32°, the dew is fro- 
zen, and then takes the name of white or lioar frost. 

It will be apparent from what we have said, that dew will occur 
most frequently when there is a considerable difference between 
the heat of the day and tho night. It is on this account that we 
seldom have dews either in mid-winter, or mid-summer, i. e. at 
the solstices, but generally just after the vernal, and before the 
autumnal equinox, viz : in May, and August. Dew is most co- 
pious in those places which are sheltered from the wind, and high 
winds therefore are a sure preventive to its formation, and of hoar 
frost. Dew and frost occur most frequently in clear weather, 
when the radiations of heat from the ground are thrown up into 
the sky without being again reflected, hence the thinnest screen, 
or the shade of a tree is a protection, and a cloth thrown over 
delicate plants will preserve them from frost. The quantity of 
moisture precipitated from the atmosphere, depenpts upon a va- 
riety of circumstances ; on the previous dampness of the com- 
mingled portions of the fluid, their difference of heat, the eleva^ 
tion of their mean temperature, and the extent of the combina- 
tion which takes place, When the deposition is slow the very 



140 



THE WOKLDv 



minute, aqueous globules remain suspended. These are found to* 
be made up of hollow vesicles, filled with air like a soap bubble ; 
and as the air included, is rarefied by the latent heat when the va- 
por is condensed, the weight of these vesicles becomes less than 
the weight of an equal bulk of air, and therefore they rise or float r 
forming a cloud. When the air within these vesicles bursts, the 
drops of rain are formed, which are changed, according to the 
sircumstanees attending their formation, as regards rapidity and" 
copiousness, or the state of the medium as to heat, into hail or 
snow. In order for the precipitation of moisture necessary to 
form rain, hail, or snow, contending currents must bring vast 
fields of air of different temperatures over a given spot, as for 
example, ^hen a warm south-east wind encounters a cold north- 
wester- In some parts of the world, as in Egypt, part of Chili, 
and Peru, it seldom rains, for there the winds usually blow in 
one direction. 

Snow is formed by the crystaTiztftion of aqueous vapor in- 
stead of its formation into drops. It is thus converted into a 
white downy substance, which falls gently toihe surface, forming 
in winter a warm covering, confining effectually the heat of the 
earth. The snow huts of the natives of Labrador are said to be 
quite warm. Below are figured some of the beautiful forms which 
tfoe snow crystals assume in cold climates, 




Hail is formed by clropi of ram suddenly congealed during their 
fall, by passing through a lower stratum of dry and cold air. The 



141 



most violent hail storms are caused by a sudden transference of 
a body of warm air up beyond the term of perpetual congelation, 
where the drops of rain are frozen into hail stones. This is some- 
times accomplished by means of whirlwinds, by which the hail- 
stones being sustained for some time, are occasionally accumula- 
ted to a very large size. By referring to our figure of the curve 
of perpetual congelation, page 126, it will be understood why 
hail storms seldom occur in the equatorial regions, and most fre- 
quently in the temperate zones*, and seldom or never in the polar 
regions. The term of congelation is too high at the equator for 
the hot air raised by a whirlwind to pass beyond, or up to it, and 
at the polar regions, the air seldom becomes as hot as is required 
to form hail storms. Different names have been given to the va- 
rious forms of clouds, derived from their appearance and charac- 
ter, we will briefly notice them. First, we have, occurring at the 
greatest elevation, the Cirrus, or curl-cloud, which is a thin fleecy 
vapor, with a waving and striated appearance as shown in the 
engraving below. This cloud is frequently called the curl-cloud 




from its flexuous form, and is not unlike a bunch of wool pulled 
out into fine pointed ends. After a continuance of fine weather 
the cirrus is often observed at great heights like a fine white line 
stretching across the sky. The peculiar form of cirrus shown in 



142 



THE WORLD. 



the engraving, called vulgarly, mare's tail, is thought to be an in- 
dication of violent winds, and the wind is generally from the 
quarter towards which the fine extended ends are pointed. When 
carefully observed, every particle of the cirrus cloud seems to be 
inmotion, though the whole cloud appears nearly stationary. This 
cloud under different circumstances, presents considerable varie- 
ty of appearance. After a continuance of clear and fine weath- 
er a whitish line of vapor stretched out like a thread, may be ob- 
served at a very great height, the e'nds seeming lost in the horizon, 
this is often the first indication of a change from dry to wet 
weather. To this line of cloud others are added, or as it were 
propagated from the sides in an oblique or transverse direction 
the whole having the appearance of net-work* 




The Cumulus, is a dense mass of rolling clouds risino- from a 
horizontal base. The name denotes a heap or pile ; it is some- 
times called the stacken-cloud, since the masses of which it is 
composed seem stacked or piled together. This cloud is gene- 
rally formed during the day, but is desolved at the approach of 
evening, it has hence been termed the cloud of day. The Stratus 
or fall-cloud is a low cloud seeming to rest upon the earth, hence 
its name stratus, a covering. This cloud is generally formed 
during the night, and is sometimes called the cloud' of night, it 
is generally dissipated by the rays of the sun and in this ease is 



CLOlJDS. 



143 



considered indicative of fine weather. Among this variety of 
clouds are included those fogs and creeping mists that in summer 
evenings fill the valleys, remain during the night, and disappear 
in the morning. The formation of the cumulus is best viewed 
in fine settled weather, about sunrise or a little after. Small 
specks of cloud will be seen in the atmosphere, which seem to be 
the result of the gatherings of the stratus or evening mists, which 
rising in the morning form into small clouds whilst the rest oflhe 
sky becomes clearer. About sunrise two or more of these unite 
and form a stack en- cloud. In the evening it again subsides giv- 
ing place to the stratus or fall cloud. In our engraving the cu- 
mulus is seen above and the stratus nearer the horizon. Some 
varieties of the cumulus are supposed to be closely connected 
with electrical phenomena. The hemispherical form is more 
perfect in fine than in changeable weather. 




The Cirro-stratus is often called a mackerel sky, and is seen 
in fine summer evenings, it is generality called the wave-cloud 
on account of its frequent alterations of figure. It is formed at 
a great height and presents many varieties and is sometimes seen 
as a thin extensive sheet covering the heavens, and it is this form 
of the cloud in which the lialos appear, which are thought to in- 
dicate raiii, and when the sun sets apparently shrouded in a dense 
stratum of this cloud it is a sure indication of a wet morning. A 



144 



THE WORLD. 



form of the cirro-stratus called the cymoid cirro- stratus, cosisting 
of rows of little clouds curved in a peculiar manner, is a sure in- 
dication of coming storms. Its most common form however is a 
flat horizontal cloud consisting of waving bars or streaks, eon- 
fused in the middle, but more distinct at the ends or edges. 




Tho Cirro-cumulus consists of extensive beds of small white 
clouds called in Germany, little sheep. It is sometnpes called the 
sonder i. e. sun( 7 er-c!oud. When the component clouds towards 
evening are large and well denned, and distinct from each other 
it is considered to indicate fine weather, on the contrary, when 
the little clouds are round and compact, accompanied by the cu- 
mulo-stratus (see next figure), it is a sure indication of an ap- 
proaching storm. It is to this cloud that Milton alludes. 

" To behold the wandering" moon, 
Riding near her highest noon, 
Like one that hath been led astray 
Through the heaven's wide pathless way ; 
And oft as if her head she bow'd, 
Stooping through a fleecy cloud." 

The eirro-euniulus generally is a forerunner of warmth, indi- 
cating, particularly when the little clouds are small and round, in 
summer an increase of temperature, and in winter the breaking 
up of a frost. The connection of this cloud with thunder stormy 



CLOUD*. 145 

has been frequently noticed by poets. In rainy and changeable 
weather it has a light fleecy texture, and is irregular in the form 
of its component parts, approaching to the cirro-stratus. 




The. Cumido-siratjis, or twain-cloud usually presents an hori- 
zontal base upon which the cloud appears heaped or piled up, it 
is of common occurrence previous to rain, and sometimes changes 
into the the nimbus or rain-cloud. In our figure, the cumulo- 
stratus is shown at the left and nimbus at the right The cumu- 
lo-stratus is usually formed out of the cumulus, which grows 
denser and spreads out laterally until it overhangs its base, while 
the tops remaining distiuctseem like so many snow-capped moun- 
tains, or rocks piled up. When the cumulo-straius increases in 
density and blackness, indicating rain, the nimbus or rain-cloud 
is formed. As soon as the actual rain commences the blackness is 
changed into a dark gray or slaty color. After the rain the clouds 
separate and form again cumuli, cirri, and cirro-cumuli, which 
float in the upper regions of the atmosphere, while the broken 
fragments of the nimbus rail along in the currents of wind 
below. 

It often happens that a cloud, in descending, enters a stratum 
qf air warmer than itself and is again converted into vapor and 



146 THE WORLD. 

absorbed, a remarkable appearance of this sort is observed oil 
the Table Mountain at the Cape of Good Hope. "Its flat top, call- 
ed the Table Land, is about two miles in length from east to west, 
and of various breadths, but nowhere exceeding a mile. The 
height is estimated at 3500 feet above the sea. It is a common 
saying among the inhabitants of Cape Town, that when the 
Devil spreads his table cloth upon the mountain you may look for 
a strong south-east wind. In the whole system of meteorology 
there is not a more infallible prognostic. The DeviPs tablecloth is 
a thin sheet of white vapor which is seen reaching over the edge 
of the precipice, while the sky all around is clear and unclouded. 
The rapidity of its descent, resembles that of water pouring over 
the face of a rock. The air, at the same time begins to be agi- 
tated in the valley, and in less than half an hour, the whole town 
is involved in dust and darkness. Instantly the streets are de- 
serted, every window and door is shut up, and Cape Town is as 
still as if it were visited by the plague. Sometimes, instead of a 
sheet of vapor an immense cloud envelopes the mountain, and 
stretching out on all sides like a magnificent canopy, shades the 
town and adjacent country from the sun. The inferior boundary 
of this cloud is regulated, probably, by various circumstances, 
among others, by the strength of the wind, and the temperature 
of the air in the Table Valley. The influence of the latter is to 
be inferred from the fact, that though the cloud never descends 
more than half way into the hot parched amphitheatre of Cape 
Town, it may be observed on the side of Camp's Bay, rolling 
down in immense volumes to the very sea, over which it some- 
times stretches farther than the eye can follow it. Nothing can 
be more singular than the appearance of this cloud. It is con- 
tinually rushing down to a certain point on the side of the moun- 
tain and there vanishing. Fleeces are seen from time to time, 
torn from its skirts by the strength of the wind, floating and 
whirling, as it were in a vortex, over the town, and then gradu- 
ally dissolving away. But the main body remains, as it were, 
nailed to the mountain, and bids defiance to the utmost efforts of 
the gale. There is a constant verdure maintained on this moun- 
tain from the moisture deposited from the atmosphere. 



CLIMATE, 147 



CHAPTER IV. 

Climale. 

st The body, moulded by the clime, endures 
Equator heat, or hypoborean frost, 
Except by habits foreign to its turn, 
• Unwise you counteract its forming pow'r." 

Armstrong, 

In the present chapter we shall very briefly consider the prom-* 
inent causes which affect the climate of the various portions of 
the earth's surface. The subject is a very important one and we 
can do little else than give the great outlines, and must therefore 
refer the reader to the more elaborate Works of Leslie, Daniel], 
and Kaemtz. 

The primary cause of all heat upon the surface of the earth, 
and its superincumbent atmosphere, is the sun, whose rays may 
also be regarded as the source of all life upon our planet. In the 
preceding pages,we have, somewhat at length, illustrated the man- 
ner in which the sun apparently changes its position in the heavens, 
traversing during the year through the twelve signs of the Zodi- 
ac, in the path called the ecliptic, which is inclined at an angle of 
23° 28' to the celestial equator, which it crosses in two opposite 
points called the equinoctial points. 

The celestial equator, we have shown to be in the same plane 
as the equator upon the earth, consequently, as the earth turns on 
its axis, it will happen that the rays of the sun, whenever it may be 
situated in the celestial equator, i. e. at ihe time of the equinoxes, 
will fall vertically, or perpendicularly upon all those places situated 
upon or near to the terrestrial equator. Twice a year, viz : on 
the 21st of March and the 2.1st of September, the sun is in those 
points of the ecliptic which cross the equator, and at this time 
its rays are vertical at noon at the equator, as we have just de- 



148 fM£ WORLD. 

scribed. At these seasons of the year the changes from winter 
to spring, and summer to autumn, commence, and the sun is said 
to be crossing the line. 

The distribution of heat in the neighborhood of the equator is 
tolerably equal, for twice during the year, viz : March 21st and 
September 21st, the sun's rays fall vertically, and they do not 
fall very obliquely at any time between these two periods* From 
the 21st of March, the sun begins to move northword of the equa- 
tor apparently, until at the 2lst of June, its angular distance from 
the equator, amounts to 23° 28'. This is the angle which the line 
S S' makes with the line E E', see the figure on page 57, the 
former representing the plane of the ecliptic, the latter the plane 
of the equator. At this time, as the earth turns on its axis, the 
sun is vertical at noon at all those places which lie in a circle 
drawn upon its surface parallel to the equator, and at an angular 
distance of 23° 28' north of it» This circle is called the tropic of 
Cancer, for a reason we have already explained. From the 21st 
of June to the 21st of September, the sun approaches the equa- 
tor, which it crosses on the latter named day, it then moves far- 
ther south, until, on the 21st of December, its angular distance 
from the equator becomes 23° 28', and, if we suppose a circle 
drawn upon the earth at a distance of 23° 28' from the equator, 
but south of it, the sun will now be vertical at all places situated 
on or near to this circle, which, for reasons already given, is called 
the iropic of Capricorn. All places therefore lying upon these 
tropics, receive once in the year, the sun's rays perpendicularly at 
mid-day, this being on the 21st of June for the tropic of Cancer 
and the 21st of September for the tropic of Capricorn. At all 
places within these two tropics the sun is vertical at noon twice 
in the year ; and at all places without or beyond them, it is never 
vertical. The nearer we approach the tropics, leaving the equa- 
tor, the more marked are the different seasons of the year, and for 
the following reason; once during the year, as we have just remark- 
ed, the sun's rays fall vertically at the tropics, and once they 
make an angle of 47° or twice 23° 28', with the direction of the 
plumb-line, and which is the angle S S'' C, see figure on page 
57, falling consequently, with considerable obliquity. The hot- 



CMIWATT!. 149 

test and coldest seasons being separated by a period of half a year, 
differ very considerably from each other in their temperature. 
The whole terrestrial zone lying- between these two tropics is 
called the hot zone, or torrid zone. When the sun's distance from 
the equator north is the greatest possible, i. e., when it is in the 
tropic of Cancer or at the point VI, see figure, page 80, the north 
pole of the earth is illuminated* and the south pole in darkness, as 
represented in the figure, page 109. If we suppose a circle traced 
upon the earth as shown at c d, it is evident that as the sun 
now illuminates all within this circle, the day will be to a specta- 
tor situated upon it, 24 hours in length, or in other words visible 
during a complete revolution of the earth on its axis. A similar 
circle shown at g //, indicates the position in the southern 
hemisphere where the longest day is 24 hours. These two cir- 
cles are called, the former tli^/Vrctic, and the latter the Antarctic, 
the former m situated 23° 2?' from the north pole, and conse- 
quently G6° 32' north of the equator, and the latter at the same 
distance from the south pole, and south of the equator. The 
terrestrial zones included between the tropics and the polar cir- 
cles, are called the northern and southern temperate zones. The 
four seasons of the year are most strongly characterized in these 
zones, and the general rule for the diminution of heat is, directly 
as the distance from the equator. Within the polar circles are 
the northern and southern frigid zones. As the earth turns upon 
its axis from west to east, the sun is apparently caused to rise in 
the east, move over the heavens, and set in 'the west, thus pro- 
ducing the alternation between day and night. During the day, 
the surface of the earth is warmed by the rays of tn"e sun, but 
when these arc withdrawn at night, the heat is radiated to the 
heavens and lost, during the night therefore the surface of the 
earth is cooled. We shall presently see that the vicissitudes in 
climate varying with the latitude, arc mainly due to the unequal 
lengths of day and night. Under the equator the days and nights 
are very nearly equal, throughout the year, each lasting 12 hours. 
As soon, however, as we leave the equator, the length of the day 
varies according to the season of the year, and the difference be- 
tween the day and night becomes more striking as we approach 



150 THE WORLD, 

nearer the pole3. The following table exhibits the length of the 
longest day for different geographical latitudes. 

Polar elevation. Length of the longest day. 

,12 hours, 

16° 44' ,13 ».• 

30° 48' 14 «« 

49°22' 16 * 

63° 23' 20 " 

66° 32' 24 " 

67° 23' 1 month, 

73° 39' 3 months, 

90° 6 months. 

Upon examining this table it will be perceived that within the 
tropics, the length of the longest day never varies much from that 
of the night, and hence, as before observed, the temperature is 
tolerably equal. In higher latitudes the rays of the sun strike 
more obliquely than within the tropes, yet the day so much ex- 
ceeding the night, more heat is gained during the day than is ra- 
diated during the night, and thus, what is lost in intensity, is gained 
in the length or duration, and it thus happens that during the 
summer it may be very hot, even at places far removed from the 
equator. At St. Petersburgh, for instance, during a hot summer 
the thermometer frequently rises to 86°. On the other hand, in 
winter, at the same latitudes, the days become as much shorter 
than the nights, as the nights were previously shorter than the days; 
hence, since the sun's rays fall very obliquely, and are therefore 
very feeble in thoir action, the earth radiating much more heat at 
night than it receives during the day, the winter temperature is 
very low, the difference between winter and summer tempera- 
ture will therefore, generally be greater, the farther we remove 
from the equator. 

H At Bogota, which is 40° 35' N. of the equator the difference 
of temperature between the hottest and coldest month amounts to 
only 3° ; in Mexico (19° 25' N. lat.) this difference is 14° ; at 
Paris, (48° 50' N. lat.) 48°, and for St. Petersburgh, (59° 56' N. 
lat.) 57°." 

It appears from what has been said, that within a distance of 10 
or 15 degrees of the equator or equinoctial line, the difference be- 
tween summer and winter temperature is trifling, but when we 



CLIMATE. 151 

get as far north a? the tropics, this difTereneee becomes very sen- 
sible, and it has been truly observed, that the torrid zone may be 
divided in three, viz : the equatorial belt, extending 10 or 15 de- 
grees from the equator, and the two belts north, and south, be- 
tween this and the tropics. The equatorial belt, properly so called, 
is temperate compared with the two others, the zone of the tropic 
of Cancer being the hottest and least habitable part of the globe. 
The greatest natural heat of which we are aware, has been ob- 
served at ^Bagdad, at 33 degrees of N. lat., being 111° Fahrenheit. 
There are many reasons why the equatorial belt should have a 
uniform and somewhat mild temperature ; the clouds, the great 
rains, the night? naturally cool and equal in length to the days, 
and the great evaporations. As we go farther from the equator 
the difference between the summer and winter temperature be- 
comes more marked, the summers being, on account of the pro- 
tracted heat of the day, very warm even in high latitudes, and true 
winters extremely cold. Thus, even as far from the equator as 
the 65th parallel of latitude, the power of tho solar beams accu- 
mulating through the long days, produces an effect which might 
be expected only in the torrid zone. There have been examples 
of forests having been set on fire, and of the pitch melting on the 
sides of ships. Notwithstanding the general law of the decrease of 
mean temperature as we recede from the equator, yet it is impos- 
sible to draw any conclusion as to the climatic relations of a place 
from its geographical latitude. If the earth's surface was entirely 
homogeneous, either covered by water, or by land, possessing 
the same capacity for heat, then the geographical latitude of a 
place would determine its climate, and all places having the same 
latitude would have a similar climate. This however, is not tho 
case, for although the local temperature of a country depends 
very much upon its latitude, yet the nature of its surface, the 
proportion of humidity, the distance from the sea, or from lakes 
or mountains, and its elevation above the ocean, and the nature 
of the prevailing winds, all have a share in determining the cli- 
mate. Tho decrease of heat as we recede from the equator fol- 
lows different laws in the two hemispheres, being greater in the 
southern than in the northern, and is also affected by the longN 



152 THE WORLD. 

tnde. The true distribution of heat over the earth's surface can 
therefore only be determined by a long series of observations. 
Baron Humbolt with unwearied zeal, has collected the data for, 
and laid the foundation of, a scientific meteorology. The instru- 
ment employed to measure the intensity of heat, called a ther- 
mometer is to well known to need any description here. The 
thermometer in ordinary use is w T hat is called Fahrenheit's, the 
scale being graduated to show 212° for the heat of boiling wa- 
ter, and 32° for the temperature of melting ice, or freezing water. 
The zero or commencement of the scale, is the temperature of a 
mixture of salt and ice, or snow, and which was once supposed to 
be the greatest artificial cold. The thermometer called Reau- 
mer's is used in some parts of the continent of Europe, the freez- 
ing point of water being zero, or the commencement of the scale, 
and the space between this and the boiling point of water is di- 
vided into 80°. The thermometer now used in France, and the 
greater part of the continent of Europe, is called Centrigrade ; 
the scale of this thermometer is graduated into 100 degrees from 
the freezing, to the boiling point of water ; this division of the 
scale appears the most natural, and' has been adopted by law in 
the state of New York. 

In employing the thermometer to observe the general tempera- 
ture of the air at any particular season of the year, it will gener- 
ally bo sufficient to make two observations in ihe morning, viz: 
at 4h, and lOh, and two in the afternoon at the samo hours, the 
mean of the observations will give the mean temperature for 
the day very exactly ; thus, suppose the observations made at 
these hours to be 50°, 80°, 90°, and 60°, adding these all together, 
and dividing their sum 2S0°, by 4 gives 70° for the mean tem- 
perature of the day. When we know the mean temperature of 
all the dats of a month, we can in like manner determine the 
mean temperature of that month. We can likewise determine 
in a similar manner the mean temperature of the year, or of 
rummer, and winter. The mean annual temperature, of a place 
not subject to very great local changes, such as the clearing up 
of forests, or drying up of streams and rivers, is very nearly con- 
stant. Thus, the extreme difference of mean annual tempera- 



lure of Paris for a series of 16 years was only 4°. We can thus 
by a series of well directed observations, determine the general 
climatic relations of various continents, and the result of such ob- 
servations are in some instances very different from what would 
be inferred from mere theoretical considerations. It is found that 
the decrease of heat as we recede from the equator, follows dif- 
ferent laws in the two hemispheres. The subjoined table shows 
the mean annual temperatures of Western Europe and North 
America, continued from the equator. 



Latitude. 


Old World. 


New World. 


Difference. 


0° 


81.5° 


81.5° 


0^ 


20 


77.9 


77.9 





30 


70.7 


67.1 


3.6 


40 


63.5 


54.5 


9.0 


50 


50.9 


38.3 


12.6 


60 


41.0 


25.0 


16.0 


70 


33.0 


0.0 


33.0 



From this table it appears that the decrease of temperature, or 
increase of cold is much more rapid in America than in Europe. 
Baron Humbolt, who has added more to our knowledge of the 
distribution of temperature over the globe, than any other who 
has labored in the same boundless field, has proposed a system of 
isothermal lines connecting different places having the same mean 
annual heat. The differences between the mean annual temper- 
ature of places upon the same parallels of latitude are thus pre- 
sented to the eye in a very striking manner. On the next page 
will be found a little chart of isothermal lines for every 5° in 
Mercator*s proportions. It will be seen that the mean annual 
heat of Eastern Asia and Eastern America, are much nearer than 
of Eastern America and Western Europe. A simple inspection 
of this map will give a clearer idea of the variation of isother- 
mal lines from the parallels of latitude. Thus, for instance, the 
mean annual heat 8t the North Cape, is 32°; whilst Nain on the 
coast of Labrador, 14° south of the North Cape, has a mean an- 
nual heat of 25°. The table which we give contains a general 
summary of Baron Humbolt's observations deduced from a very- 
great number of observations. The locality of a place very 



154 



THE VVORLb. 



r>J ■— 




« 5 l1 as p 



CLIMATE. l0J 

much affects the climate, and as a general rule the western sides 
of continents and largo islands, arc warmer than the eastern. Cer- 
tain portions of the globe, which from their nearness to the equa- 
tor would bo extremely warm, are rendered tolerably cool by their 
elevated situations. This is the case with much of the tropical 
land in America, which is so raised that it rivals even European 
climates in mildness and agreeable temperature. The air of these 
elevated tropical districts is remarkably pure and transparent, and 
the winds which sweep over the plains, are cooled by their pass- 
age down the snow-capped mountains, which rear their bright 
summits to the skies. The vast expanse of table-land, forming 
the empire of Mexico is of this character, being elevated 7000 
feet above the level of the ocean. This land in many parts has 
the fertility of a cultivated garden. The plains of Columbia in 
South America, and indeed all along the ridge of the Andes, are 
similarly situated. The chart which we have given represents 
the direction of the isothermal lines, or lines connecting places 
which have the same mean annual heat. It will be evident that 
places may thus be situated on the same isothermal line, which 
have very unequal mean temperatures of summer and winter. 
We need only refer to the table on page 157, to be convinced of 
this. Thus, the mean annual temperature of London, and Cam- 
bridge, Mass. is the same, 50°36'; but the mean temperature o 
the warmest month at London is 64°40', while at Cambridge it 
is 72°86', and of the coldest month, at London 37°76, at Cam- 
bridge 29.84, London therefore has a colder summer and a warm- 
er winter than Cambridge. The reason of this, is undoubtedly, 
the insular situation of the former, for as a general rule the ex- 
tremes of temperature are experienced in large inland tracts, and 
little felt in islands remote from continents. The difference be- 
tween the mean temperature of summer and winter is nothing at 
the equator, and increases continually with the latitude. When 
the mean annual temperature is low the difierences between the 
extremes of the seasons is great, and the contrary. 

The effect of climate upon the geographical distribution of 
plants and animals is very marked Each, generally has its pe= 



156 THE WORLD. 

culiar climate where it thrives best, and beyond certain limits it 
ceases to exist. The successive zones of vegetation, as we recede 
from the equatorial regions, have sometimes been supposed to be 
represented by the diffe rent altitudes upon the mountains under 
the equator, as it is evident we have in ascending from the valleys 
to their snow-capped summits, every variety of temperature. 
The analogy fails however in one essential point, for as we ascend 
the mountains the pressure of the atmosphere is continually di- 
minished and it is evident that less nutriment is thus afforded for 
the growth of the plant. The influence which the variations of 
climate alluded to, must have upon vegetation is very evident, 
thus in many parts of Siberia, wheat and rye are raised upon a 
soil which is constantly frozen at a depth of three feet, while in 
Iceland, where the mean temperature of the year is much warm- 
er, and the winter's cold but inconsiderable, it is not possible to 
raise any of the ceralia or common grains, as the low summer 
temperature does not suffer them to ripen. It is for the same 
reason that the vine does not flourish in England, for although 
it can endure a tolerably great degree of cold, yet it requires a 
hot summer to make the fruit ripen, and yield a drinkable wine. 
There is no subject connected with meteorology which requires a 
more careful, and studied investigation than that of climates. 
So many causes influence the temperature of the air, and some 
of them are so variable, that no labor short of a well conducted 
series of observations, extending through a long course of years 
can give a satisfactory result. In the brief account we have given, 
we have been able to present little else than the leading facts, 
and must refer the reader to the writings of Leslie, De Candolle, 
Mirbel, and Humbolt, for further information. 



*I ; A.fcLE OF TEMPERATURES. 



157 



TABLE 

Exhibiting tfie mean temperature of various places compiled prin- 
cipally from the observations of Biron Alex. Von Humboldt. 



Isother- 
mal 
Bands. 


Names of Places. 


Position. 


Mean 
tempera- 
ture of 
the Year. 


• Lat. 


Long. 


Hght. 


o 

00 

s 

o 

u 

3 


Melville Island 


O 1 

74 47 
57 8 
68 30 
46 30 
71 
65 3 
63 50 

59 56 
63 24 
55 45 

60 27 


o / 
110 48w. 
61 20 w. 
20 47e. 
8 23e. 
25 5'^)e. 
25 26e. 
20 16e. 
30 19e. 
10 22e. 
37 32e. 
22 18e. 


Feet 

o 



1356 

6390 











970 




o 
— 2 00 
+26.42 
26.96 
30.38 
32.00 
35.08 
33.26 
38.84 
39.92 
40.10 
40.28 


Nam 


EnontekLes 

Hospice de St. Gothard. . . 

North Cape 

Uiea 

Umea 

St. Petersburg 

Drontheim 


Moscow 


Abo 




o 

3 
o 

s 

o 

s 
n 


Upsal 

Stockholm 

Quebec 


59 51 
59 20 

46 47 
59 55 

47 47 
55 41 

54 17 
51 25 

50 5 

51 32 

47 22 

55 51 

52 14 
46 50 

53 21 
46 5 
46 12 
49 29 

48 12 


17 38e. 

18 3e. 
71 Uw. 
10 48e. 
10 34e. 
12 35*. 

2 46w. 
59 59w. 
14 24e. 

9 53e. 
8 32e. 

3 lOw. 
21 2e. 







3066 




456 

1350 

150 




42.08 
42.26 
41.74 

42 80 
42.98 
45.68 
46.22 
46.94 
49.46 
46.94 
47.84 
47.84 
48.56 
48.92 
49.10 
49.28 
49.28 
50.18 
50.54 


Christiania 


Convent of Peissenberg 

Copenhagen 

Kendal 


Falkland Islands 


Prague 

Gottingen 

Zurich 

Edinburgh 

Warsaw 


Coire 

Dublin 


9 30e. J1876 

6 19w. 

7 26e. 1650 
6 8e. |1080 

8 28e. .432 
16 22e. 420 


Berne 


Geneva 


Manheim 


Vienna ► 









*58 



THE WOXLP. 



fsolfter 

mal 
Bands. 



Names of Places- 



Position. 



Mean 
tempera- 
ture of 
the Year. 



Lat. Long. light, 



o 
o 






Clermont 

Buda 

Cambridge, Mass, 

Paris 

London #. . . 

Dunkirk * 

Amsterdam 
Brussels c . r . * . . • . 
Franeker ....... 

Philadelphia*... . 

New York * 

Cincinnati 

St. Malo 

Nantes 

Peking 

Milan 

Bordeaux 

Marseilles 

Montpellier 

Rome 

Toulon 

Nangasaki » 

Natchez 

Funchal 

Algiers 

Cairo 

Vera Cruz 

Havana 

Cumana 



45 46 

47 29 
42 22 

48 50 
51 30 

51 2 

52 22 
50 50 
52 36 

39 56 

40 40 
39 6 
48 39 
47 13 
39 54 
45 28 
44 50 



5e. 
Ie. 

7w. 

20e. 

5w. 

22e. 

50e, 

22e. 

22e. 

75 lOw. 

73 58w. 

84 27w. 

2 lw. 

1 32w. 

116 27e. 

9 He. 

34w. 



3 

19 
71 
2 

2 
4 
4 
6 



Feet 
1260 

494 


222 








510 




390 




50.00 

51.08 

50.36 

51.08 

50.36 

50.54 

51.62 

51.80 

51.8 

53.42 

53.78 

53.78 

54.14 

54.68 

54.86 

55.76 

56.48 



J* 



43 17 
43 36 
41 53 
43 7 
32 45 
31 34 



5 22e. 

3 52e. 

12 27e. 

5 50e. 

129 55e. 

91 24w. 








180 



59.00 
59.36 
60.44 
62.06 
60.80 
64.76 



68° to 

72°. 






32 37 

36 48 



16 56w, 
3 Ie. 



30 2 
19 11 
23 10 
10 27 



30 18e. 
96 lw. 
82 13w. 
65 15w. 



68.54 
69.98 

72.32 

77.72 
78.08 
81.86 






THE ATMOSPHERE, 151) 



CHAPTER V. 

Optical Phenomena. 

54 Why do those cliffs of shadowy tint, appear 
More sweet than all the landscape smiling- near ? 
'Tis distance lends enchantment to the view, 
And robes the mountain in its azure hue." 

Campbell. 

In the present chapter we shall describe and explain the general 
optical appearance of the sky, and some of the more striking op- 
tical phenomena connected with our present subject. When the 
rays of the sun strike the minute particles of air, which, accord- 
ing to circumstances, maybe more or less dense, or charged with 
watery vapor, they are either reflected, or transmitted ; in either 
case sometimes returning the most beautiful colors. It is a fact 
to well known to need much illustration from us, that light, when- 
ever it is refracted by any medium", such as glass or water, is al- 
ways separated into the prismatic colors, whenever the surfaces 
of the medium are curved, or inclined to each other. It is not 
however, so generally understood, that these different colored 
rays have different powers of penetrating through various media, 
and that they move with different velocities. This however, is 
susceptible of demonstration, and it is to this that the beautiful 
colors of an autumnal sunset are owing. The red, violet and 
orange rays have the greatest velocity, and penetrate the thick 
dense strata of horizontal air, with the greatest facility, giving us 
the rich and brilliant hues of sunset and sunrise, tinging the 
morning and evening clouds with glowing red, and gold ; and 
the sober twilight, with that purple fading into gray which is assum- 
ed when the ruddy glare of sunset is tempered by the azure of 
the sky. Since the red and yellow rays which compose white 
light, are transmitted by the air, unattended by the blue rays, it 
follows that these latter must be reflected, hence the beautiful 



160 THE WORLD, 

blue of the sky, and the bright azure which tinges the distant 
mountains when viewed through a considerable body of inter- 
vening air, and especially, when charged with watery vapor 
Perhaps this one feature, which so mellows down the distant out- 
lines of the hills and buildings, is the most pleasing feature of 
the landscape. It is from strict attention to the phenomena de- 
pendent upon this principle, that the artist derives his pleasing 
skill in picturing objects of varying distance, introducing skill- 
fully the color of the intervening air. How simple, and yet how 
beautiful are the various contrivances which administer, not to 
the wants merely, but to the pleasures of man. It is the same 
simple cause which tints the bright blue sky, and its beautiful 
clouds, here piled in snowy masses, and there sundered into a 
thousand fleecy shapes; which lights the west with a golden glow, 
and fringes the extended clouds that skirt the horizon with the 
brightest hues of red and gold ; and it is owing to the peculiar 
nature of the red rays of the spectrum, that the sun appears a 
dull red globe when viewed through air highly saturated with 
watery vapor, or through clouds and fogs. 

When the rays of the sun strike upon a cloud, they are copi- 
ously reflected, but partly absorbed by the minute suspended glo- 
bules, and the quantity of light which penetrates through the 
nebulous medium is always much less than what traverses an 
equal body of air, and this gives the clouds their varying shades 
of color. That the color of the sky is owing to reflected light, is 
sufficiently evident from the fact, that it becomes darker and 
darker, as we ascend into the higher regions of the atmosphere, 
through which, the blue rays find a ready passage. Were it not 
for the reflecting power of the atmosphere, and the clouds, we 
would have no softening of the day into night, as now, by the 
twilight; but instantly, at sunset, darkness would veil the earth, 
and every cloud that obscured the sun would cause a total eclipse. 
The tint of the sky is deeper in the torrid zone than in high lati- 
tudes, and in the same parallel it is fainter at sea than on land, 
this may be attributed to the aqueous vapor continually rising 
towards the higher regions of the air from the. surface of the sea. 
The presence of much moisture is also easily detected by the 



/ 



HALOS. 161 

paleness of the sun at sunset, by means of which, sailors are ac- 
customed to presage a storm. 

The colored rings or halos which are often seen surrounding 
the sun and moon are evidently occasioned by very thin vapor 
diffused through the atmosphere. They are supposed chiefly to 
encircle the moon, but scarcely a day passes without light misty 
clouds, when at least portions of halos may be seen near the sun, 
and in order to perceive them, it is only necessary to remove 
the glare of light which makes the delicate colors appear white. 
Thus, if we examine the reflection from a smooth surface of wa- 
ter, we will perceive that the sun gilds the fleecy clouds with seg- 
ments of beautifully colored rings. This effect is more distinctly 
seen, if the rays from a hazy or a mottled sky, be received upon a 
sheet of white paper held before a small hole in the window shut- 
ter in a dark room. But even when the sun shines from an azure 
firmament, circles of the richest tints may be produced by experi- 
ment, thus, holding a hot poker below, and a little before the small 
hole in the shutter, above mentioned, throw a few drops of wa- 
ter upon it, and the sun will be painted upon the paper like the 
glowing radiations of the passion flower. 

Halos are produced by what is termed the diffraction of light, 
i. e. the rays of light in passing near the edges of a body appear 
to be bent from their rectilineal course. This diffraction may be 
easily observed by viewing objects through a minute hole, it will 
be found that the edges of straight bodies will be curved if viewed 
near the edge of the hole, and a line of bright white light, will 
appear tinged with orange on the side nearest the edge of the 
hole, and with blue upon the other. Halos are much more com- 
mon in the northern latitudes than in warmer climates, a fact 
which is owing doubtless, to frozen particles of water floating in 
the air, though Humboldt remarks that lunar halos are much 
rarer in the northern than the southern countries of Europe, and 
seen more especially when the sky is clear and weather settled. 
He observes that in the torrid zone they appear almost every night, 
and often in the space of a few minutes disappear several times. 
Between the latitude of 15° N. and the equator, he has seen 
small halos around the planet Venus. The next figure exhibits 



1G2 



THE WORLD, 



a halo seen around the sun by Schemer in 1530. In this fine set 
of halos mock images of the sun at the intersection of the cir- 
cles, termed parhelia and anthelia may be observed. These are 




quite common in the arctic regions, presenting the gorgeous ap- 
pearance of intersecting luminous arches, studded with opposite 
and transverse images of the sun ; the formation of these, is 
undoubtedly owing to the combined reflections of the rays from 
the natural faces of the snowy crystals floating abundantly in the 
air. Fringes of colored light, similar to those which form halos, 
may be observed in looking through the fibres of a feather, or 
thin streaks of grease rubbed over a glass plate. If a small hole 
is made in a piece of tinfoil, and held close to the eye, a halo 
will be seen upon looking at the sun through it, very near to his 
disc. By comparing the artificial halos thus formed with the 
natural ones, Prof. Leslie endeavored to ascertain the size of the 
globules producing the halos, it being inferred that an aqueous 



USIRA-GE. 163 

globule of the same dimensions as the perforation might produce 
a similar halo. He found them to vary from the 5000th to the 
50,000th part of an inch in diameter. When the halo approach- 
es nearest to the body, the largest globules are floating, and there- 
fore the atmosphere is surcharged with humidity. Hence the 
justness of the vulgar remark, that a dense halo close to the moon 
portends rain. 

The elevation of coasts, ships, and mountains, above their 
usual level has long been known under the name of looming, 
and the name mirage has been given by the French to the same 
phenomena. The curious spectacle often witnessed at the straits 
of Messina called stho Fata- Morgana, belongs to the same class of 
optical phenomena. One of the most interesting cases on record 
was witnessed by Capt. Scoresby, in the Arctic sea. While nav- 
igating the Greenland sea on the 28th of June, 1820, he observed 
about eighteen or nineteen sail of ships at the distance of from 
ten to fifteen miles. He saw them from the mast-head begin- 
ning to change their form, one was drawn out or elongated in a 
Fertical plane, another was contracted in the same direction, one 




had an inverted image immediately above it as at a; and two at h 
and c, had two distinct inverted images in the air ; along with 
•these images there appeared images of the ice, as at b and c, in 
two strata, the highest of which had an altitude of about fifteen de- 
grees. In a later voyage performed in 1822, he saw his father's 
ship when below the horizon. "It was" says he, "so well de- 
nned that I could distinguish by a telescope every sail, the genera 



164 THE WORED. 

rig of the ship, and its particular character, insomuch that Icon- 
fidently pronounced it to be my father's ship, the Fame, which it 
afterwards proved to be, though in comparing notes with my fa- 
ther, I found that our relative positions at the time gave our dis- 
tance from one another very nearly thirty miles, being about 
seventeen miles beyond the horizon, and some leagues beyond 
the limit of direct vision. I was- so struck by the peculiarity of 
the circumstance, that I mentioned it<to the officer of the watch, 
stating my full conviction that the Fame was then cruising in the 
neighboring inlet." 

A fine exhibition of mirage was witnessed at Cleveland on the 
afternoon of April 12, 1848, at half past three o'clock, P. M., 
and which is represented in the engraving below. The steam- 
boat New Orleans left Fairport, 30 miles from Cleveland, at 3h. 
10m. P. M., and consequently at the time the mirage was seen,, 
was below the horizon ; with a glass however, two distinct ima- 
ges were perceived elevated in the air, and a point of land ordi- 
narily invisible could be easily observed. This phenomenon was 
witnessed by a large number of persons. 




These phenomena, which we have repeatedly witnessed, are 
owing to peculiar states of the atmosphere as regards density and 
moisture. , Every one is aware that a straight stick appears to be 
crooked when thrust into the water, bending at the plrne of th» 
surface, and when a ray of light passes from one medium to an- 
other this refraction or bending always occurs, in a greater or less 
degree, according to the difference of density in the media, ok 
the peculiar refracting power. The effect of atmospheric refrac- 
tion is always to make a body appear higher than it really is, thus 
We see the sun, actually after sunset, the rays which proceed fronx 



METEORIC SHOWERS. 165 

it up into the sky, being so bent downwards as to reach the eye. 
Among the most beautiful phenomena that greet the eye when 
contemplating the heavens in a serene night, but more particu- 
larly in autumn, the shooting stars, or meteors are preeminent; at 
almost all seasons of the year an attentive observer will perceive 
them moving swiftly over the heavens, and occasionally leaving 
a long luminous train behind. Their origin has not been satis- 
factorily traced, yet, since their occurrence in unusual numbers, 
and splendor, is now proved to be periodical, it is supposed they 
may be in some way connected with that beautiful luminous ap- 
pearance called the zodiacal light. This is the opinion of Prof. 
Olmsted, who has devoted much time to this subject, and has 
been a careful investigator of the facts connected with meteors 
and the zodiacal light for many years. The •• falling stars" seem 
to have been observed in the earliest times, and were considered 
as a presage of violent winds, thus Virgil — 

" And oft before tempestuous winds arise, 
The seeming stars fell headlong from the skies, 
And shooting through the darkness, gild the night 
With sweeping lines, and long trains of light." 

The number of meteors visible at ordinary seasons of the year in 
one night, is quite limited, but we must remember that many of 
them are very small, and probably too distant to be observed by the 
unassisted eye. We have often witnessed the passage of meteors 
through the field of view of a night-glass when sweeping the 
heavens for comets, and have occasionally seen some very beau- 
tiful trains not at all visible to the unassisted eye. 

In the year 1833 a most remarkable display of falling stars 
was witnessed in the United States, but was not seen either in 
South America or Europe. It occurred on the morning of Nov. 
13th, atid exceeded in magnificence # any natural phenomenon we 
have ever witnessed ; the whole heavens seemed glowing with 
fire-balls, which were falling in all directions. For many suc- 
cessive years this exhibition was repeated on the same morning, 
occurring most abundantly at about 4 o'clock, and apparently ra- 
diating from one centre, but each year their numbers diminished, 
and we believe that now, no more are visible upon on that night 



166 



THE WORLD. 



than upon any other. Two other periods of unusual brilliancy 
seem to have been pretty well determined, viz : April 21st, and 
Aug. 10th. It is our opinion that these meteors, and the zodiacal 
light, are both of terrestrial origin, i. e. have their origin within 
the limits of our atmosphere. The greatest height at which these 
bodies occur is supposed to be about 2300 miles : at this height 
the atmosphere would be excessively rare, but it is probable that 
the upper strata are composed of more inflammable materials 
than common air ; hydrogen gas is continually being emitted by 
the great laboratory of nature, and ascends to the upper regions, 
here, when released from pressure it may expand to at least the 
distance, (and beyond it), where meteors occur. Sir John Les- 
lie thus accounts for the lambent glow of the heavens in a clear 
night, supposing this stratum of highly inflammable gas to be 
phosporescent. We might perhaps trace the zodiacal light to the 
same source. This remarkable appearance is most conspicuous 




in the finer climates and near the vernal equinox, and has often 
been ascribed to the extension of a supposed luminous atmos- 



ZODIACAL LIGHT. 167 

phere about the sun. Laplace seems to have shown satisfactorily 
that such an atmosphere, far from extending to the earth, would 
not reach to even the orbit of Mercury, If this be so, we must 
either adopt the theory of Von Humboldt, who supposes it to be a 
luminous ring surrounding the sun, or conclude it is of terrestrial 
origin. The preceding cut represents this beautiful phenom- 
enon. It may be seen in our northern latitude in the spring months 
after sunset, reaching up in the plane of the ecliptic towards the 
Pleiades long after sunset; it gradually sets with the stars and may 
again be seen in the morning before sunrise. According to Sir 
John Leslie, the sun, shining upon the higher strata of the at- 
mosphere, whichjie supposes phosphorescent, would form a large 
luminous circle which we would see surrounding the sun at noon, 
provided it was not eclipsed by his superior brilliancy; after sun- 
set it would appear as a segment of a circle, did not the vapors of 
the horizen obscure its extreme and faintest limits, hence it appears 
lenticular, or lens shaped as represented in the engraving 

We shall conclude this chapter with a description of that well 
known, but yet unexplained phenomenon the Aurora Borealis or 
northern lights. In the high northern latitudes, beautiful dis- 
plays of the aurora are witnessed, and they serve to enliven the 
long winter nights with their bright coruscations. In our latitude 
the exhibitions are of a less beflptiful character, and rarer, but yet 
so frequent that they are familiar to all. It generally appears 
like a bank, or cloud of light, of a pale yellow color, resting upon 
the northern horizon, occasionally emitting streamers which shoot 
up towards the zenith, and then fade, revive again, and subdivide. 
At other times it is seen as a luminous arch rising a short dis- 
tance above the horizon, its highest altitude being in the magnet- 
ic meridian ; from this, streamers ascend, and if the display is a 
fine one, will appear to unite in a circle nearly in the zenith, called 
the corona. It is a remarkable fact that great displays of the 
aurora are always preceeded by a disturbance of the magnetic 
needle. Like the meteoric showers, there seems to be a periodi- 
cal return of the auroral displays in unusual splendor, after defi- 
nite intervals. One of these returns, which we well remember, 
occurred at intervals from November 1835, jto May 1836. The 



168 THE WORBB. 

tWo following descriptions are from the pen of Professor Olmsted, 
The first display took place on the 17th of November 1835, the 
last on the 23d of April 1836. 

44 On the 17th of November, 1835, our northern hemisphere 
was adorned with a display of auroral lights remarkably grand" 
and diversified. It was observed at fifteen minutes before seven 
o'dock, when an illumination of the whole northern sky, resem- 
bling the break of day, was discernable through the openings in 
the clouds. About eighteen degrees east of north, was a broad' 
column of shining vapor tinged with crimson, which appeared' 
and disappeared at intervals^ A westerly wind moved off the- 
clouds, rendering the sky nearly clear by eight o'clock, when two> 
broad, white columns, which had for some time been gathering 
between the stars Aquila and Lyra on the west, and the Pleiades 
and Aries on the east, united above, so as to complete a lumin- 
ous arch, spanning the heavens a little south of the prime verticals 
The whole northern hemisphere, being more or less illuminated, 
and separated from the southern by this zone, was thrown into 
striking contrast with the latter, which appeared of a dark slate 
color, as though the stars were shining through a stratum of black 
clouds. The zone moved slowly to the south until about nine 
o'clock, when it had reached the bright star in the Eagle in the 
west, and extended a little south of the constellation Aries in the 
east. From this time it began to recede northward, at nearly a 
uniform rate, until twenty minutes before eleven, when a vast 
number of columns, white and crimson, began to shoot up, sim- 
ultaneously, from all parts of the northern hemisphere, directing 
their course towards a point a few degrees south and east of the 
zenith, around which they arranged themselves as around a com- 
mon focus. The position of this point was between the Pleiades 
and Alpha Arietis, and south of the Bee. 

Soon after eleven o'clock, commenced a striking display of 
those undulatory flashes denominated merry dancers. They con- 
sisted of thin waves or sheets of light, coursing each other with 
immense speed. Those undulations which play upon the sur- 
face of a field of rye, when gently agitated by the wind, may give 
the reader a faint idea of these auroral waves, One of these 



AURORA B0REALIS, 169 

crimson columns, the most beautiful of all, as it ascended to- 
wards the common focus crossed the planet Jupiter, then at an 
altitude of thirty-six degrees. The appearance was peculiarly 
interesting-, as the planet shone through the crimson clouds with 
its splendor apparently augmented rather than diminished. 

A few shooting stars were seen at intervals, some of which 
above the ordinary rnagnilude and brightness. One that came 
from between the feet of the Great Bear, at eight minutes after 
one o'clock, and fell apparently near to the earth, exhibited a very 
white and dazzling light and as it exploded scattered shining frag- 
ments very much after the manner of a sky rocket. 

As early as seven o'clock, the magnetic needle began to show 
unusual agitation, and after that it was carfully observed. Near 
eleven o'clock, when the streamers were rising and the corona 
forming, the disturbance of the needle was very remarkable, 
causing a motion of one degree and five minutes, in five minutes 
of time. This disturbance continued until ten o'clock the next 
morning, the needle having traversed an entire range of one de- 
gree and forty minutes, while its ordinary deflection is not more 
than four minutes. 

Another writer, speaking of the same appearance, says — We 
can compare the spectacle to nothing but an immense umbrella 
suspended from the heavens, the edges of which embraced more 
than half the visible horizon ; in the south-east its lower edge 
covered the belt of Orion, and farther to the left the planet Ju- 
piter shone in all its magnificence and glory, as through a trans- 
parency of gold and scarlet. The whole scene was indescribably 
beautiful and solemn. It was a spectacle of which painting and 
poetry united can give no adequate idea, and which philosophy 
will fail to account for to the satisfaction of the student of nature, 
or the disciple of revelation. The cause can be known only to 
Him at whose bidding 

Darkness fled — Light shone, 
And the etherial quintessence of heaven 
Flew upward, spirited with various forms 
That rolled orbicular, and turned to stars. 

The appearance of April 23d 1836, is thus described by Olm- 



170 THE WORLD. 

sted : — Last night we were regaled with another exhibition of the 
auroral lights, in some respects even more remarkable than that 
of the 17th of November. . It announced itself as early as a quar- 
ter before eight o'clock, by a peculiar kind of vapor overspread- 
ing the northern sky, resembling a thin fog, of the color of dull 
yellow, slightly tinged with red. From a bank of the auroral 
vapor that rose a few degrees above the northern horizon, a great 
number of those luminous columns called streamers ascended to- 
wards a common focus, situated, as usual, a little south and east 
of the zenith, nearly or perhaps exactly at the magnetic pole of 
the dipping-needle. Faint undulations played on the surface of 
the streamers, affording sure prognostics of an unusual display of 
this mysterious phenomenon. The light of the moon, now near 
its first quarter, impared the distinctness of the auroral lights, but 
the firmament throughout exhibited one of its finest aspects. The 
planet Venus was shining with great brilliancy in the west, fol- 
lowed at small intervals by Jupiter and the moon; while the larger 
constellations, Orion and Leo, with two stars of the first magni- 
tude, Sirius and Procyon, added their attractions. The sky was 
cloudless, and the air perfectly still. 

There are but few examples on record of the auroral lights dis- 
playing themselves with peculiar magnificence in moonlight. 

Notwithstanding the presence of the moon, by half past ten 
o'clock, the auroral arches, streamers, and waves began to exhibit 
the most interesting appearances. No well-defined arch was 
formed, but broad zones of silvery whiteness, composing greater 
or less portions of arches, were seen in various parts of the heav- 
ens. Two that lay in the south, crossing the meridian at differ- 
ent altitudes, were especially observable. From each proceeded 
streamers, all directed towards the common focus. At the same 
time, those peculiar undulations called merry dancers, were flow- 
ing in broad and silvery sheets towards that point, writhing around 
it in serpentine curves,, and often assuming the most fantastic 
forms. The swiftness of their motions, which were generally 
upward, and often with their broadest side foremost, was truly 
astonishing. Toward the horizon the undulations were compara- 
tively feeble; but from the elevation of about thirty degrees to 



AURORA BOREALIS. 



171 



the zenith, their movement was performed in a time not exceeding 
one second, — a velocity greater than we have ever noticed be- 
fore, which was still distinctly progressive. 

Five minutes after eleven o'clock, a few large streamers, of 
the whiteness of burnished silver, radiated from the common 
focus towards the east and the west. These were soon superse- 
ded by a mass of crimson vapor, rising simultaneously a little 
south of west, and north of east, and ascending towards the focus 
in columns eight or ten degrees broad below, but tapering above; 
these disappeared in about ten minutes, and the lights were sub- 
sequently a pure white, except an occasional tinge of red. During 
the appearance of the crimson columns a rosy hue was reflected 
from white houses and other favorable surfaces, imparting to 
them an aspect peculiarly attractive. 

From this time until half past two o'clock, our attention was 
almost wholly absorbed in contemplating the sublime movements 
of the auroral waves : they evidently were formations entirely 
distinct from the columns, which either remained stationary, or 
shot out a broad stream of white light towards the focus, while 
the waves apparently occupied a region far below them. 

At half past two o'clock, a covering of light clouds was spread 




over a large portion o r the sky, and our observations were dis- 



172 



THE WORLD. 



continued. At this time, although the moon was down, yet its 
absence produced little change in the general illumination ; the 
landscape appeared still as if enlightened by the moon, and it 
was easy to discern the time of night by a watch, from the light 
of the aurora." 

On the preceding page, is a view of the Aurora as witnessed by 
the French philosophers in the year 1838 — 9, at Borekop, bay of 
Alten, coast of W. Finmark, lat. 70° N. It presented the form of a 
scroll with folds overlapping, and waving like a flag agitated by the 
wind. Its brightness varied very suddenly, and the colors changed 
from bright red at the base, to green in the middle portions, and 
yellow at the top. The brightness would diminish, and colors 
fade, sometimes suddenly, and sometimes by slow degrees. After 
this, the fragments would be gathered, and the folds reproduced; 
the beams seemed to converge at the zenith which was doubtless, 
the effect of perspective. 




\n I 



imsmm^m 




But it is in the Arctic regions that this phenomenon is witnessed 
in its greatest splendor, and presenting a variety of the most 
beautiful tints. In that cold region, clouds seldom obscure the 
sky, nothing in the form of fog or mist veils the deep blue of the 



AURORA BOREAIJS. 17S* 

heavens, every star blazes forth like a diamond, and a thousand; 
icy pinnacles throw hack their light, accompanied with magnifi- 
cent prismatic displays. The bold hunters who penetrate the- 
arctic circle in the pursuit of the silver fox and the sable, witness 
its grandest exhibitions. The whole sky is lighted up with the-- 
bright coruscations, and it is said that a rushing sound, like that, 
of winds sweeping; over a distant forest is heard. The inhabit- 
ants of the Shetland islands call the streamers merry dancers. 

The appearance of the aurora, and the emotions it excites, are- 
thus beautifully described by Whittier: 

A light is troubling Heaven ! A strange, dull glow 
Hangs like a half-quench'd veil of fire between 
The blue sky and the earth ; and the shorn stars 
Gleam faint and sickly through it. Day hath left 
No token of its parting,, and the blush 
With which it welcomed the embrace of Night, 
Has faded from the blue cheek of the West ; 
Yet from the solemn darkness of the North, 
" Stretch'd o'er the empty place" by God's own hand^ 
Trembles and waves that curtain of pale fire, 
Tinging with baleful and unnatural hues 
The winter snows beneath. It is as if 
Nature's last curse— the fearful plague of fire, 
Were Avorking hi the elements, and the skies 
Even as a scroll consuming.. 

Lo, a change ! 
The fiery wonder sinks, and all along 
The dim horizon of the clouded North 
A dark, deep crimson, rests a sea of blood- 
Untroubled by a wave. And over all 
Bendeth a luminous arch of pale, pure white,. 
Clearly contrasted with the blue above, 
And the dark red beneath it. Glorious ! 
How like a pathway of the Shining Ones, 
The pure and beautiful intelligences 
Who minister in Heaven, and offer up 
Their praise as incense ; — or like that which rossr 
Before the pilgrim Prophet, when the tread. 
Of the most holy angels brighten 'd it, 
And in his dream the haunted sleeper saw 
The ascending and descending of the blest !: 

And yet another change ! O'er half the sky 
A long, bright flame is trembling like the sworcS 
Of the great angel, at the guarded gate 



174 THE WORM). 

. Of Paradise, when all the holy streams 
And beautiful bowers of Eden land blush'd red 
Beneath its awful waving, and the eyes 
Of the lone outcasts quailed before its glare, 
As from the immediate questioning of God. 

And men are gazing to these " signs m Heaven" 
With most unwonted earnestness ; and fair 
And beautiful brows are redd'ning in the light 
Of fehi§ strange vision of the upper air : 
Even as the dwellers of Jerusalem, 
Beleaguered by the Roman, — when the skies 
Of Palestine were thronged with fiery shapes, 
And from Antonia's tower the mailed Jew 
Saw his own image pictured in the air 
Contending with the heathen ; and the priest 
Beside the temple's altar veiled his face 
From that fire-written language of the sky. 

Oh, God of mystery ! these fires are thine ! 
Thy breath hath kindled them, and there they burn, 
Amid the permanent glory of Thy heavens, 
That earliest revelation, written out 
In starivy language, visible to all, 
Lifting unto Thyself the heavy eyes 
Of the down looking spirits of the earth ! 
The Indian leaning on his hunting bow, 
Where the ice mountains hem the frozen pole, 
And the hoar architect of Winter piles 
With tireless hand his snowy pyramids,, 
Looks upward in deep awe — while all around 
The eternal ices kindle with the hues 
Which tremble on their gleaming pinnacles, 
And sharp, cold ridges of enduring frost, — 
And points his child to the Great Spirit's fire* 

Alas ! for us who boast of deeper lore, 
If, in the maze of our vague theories, 
Our speculations, and our restless aim 
To search the secret, and familiarise 
The awful things of nature, we forget 
To own Thy presence in Thy mysteries * 






THE WORLD 



PART III. 



PHYSICAL STRUCTURE OF THE EARTH, 



CHAPTER 1. 

Structure of (lie Earth. 

*' Ye mighty ones who sway the souls that go 
Amid the marvels of the world below! 
Ye, silent shades, who sit and hear around! 
Chaos! and streams that burn beneath the ground! 
All, all forgive, if by your converse stirred, 
My lips shall utter what my ears have heard; 
If I shall speak of things of doubtful birth, 
Deep sunk in darkness, as deep sunk in earth*' ' 

Virgil. 

We have before shown that our globe is a planetary orb of a 
Few thousand miles in diameter, and of a spheroidal shape, the 
difference between the polar, and equatorial diameters being 
twenty-six miles. The mean density of the earth, is about five 
times that of water, the interior being double that of the solid su* 
perficial crust, hence if the interior of the earth be cavernous, 
its crust must be composed of very dense materials. The crust, 
or outer covering of the earth, significantly called " Erdrinde," 
or Earth-rind, by the Germans, is that part to which our investi- 
gations are naturally directed. The greatest thickness of this su- 
perficial crust, which man has been able to explore, estimated 
from the highest mountain peaks, to the greatest natural or arti- 
ficial depths, does not exceed ten miles ; this, in comparison with 
the diameter, 8000 miles, is a distance, utterly insignificant, bear- 



17 



TllE WOULD. 



ing about the same relative proportion, as the thickness of this pa- 
per to an artificial sphere a foot in diameter. The inequalities 
and crevices in the varnish of such a sphere, would proportion- 
ately represent the highest mountains, and deepest valleys. In 
the following diagram, from the Penny Cyclopedia, the relative 
proportions of the crust of the earth, and the inequalities of its 
surface, as compared with the mass of our planet, are attempted 
to be shown. 





The line from e to It, ^presents a depth of 500 miles, to the 
point i, a depth of 100 miles, and to the line b, 45 miles above 
the surface, the supposed limit of the earth's atmosphere. The 
dark line represents a thickness of ten miles, the estimated thick- 
ness of the crust of the earth ; the points d c f g, indicate the 
altitudes of the highest mountains in the world. The highest 
peak in Europe, being Mont Blanc, which is 15,660 feet above 
the level of the sea ; and in America, Mount Sorata, Andes, 25,- 
400 feet, and in Asia, Chumularee, Himalayan, estimated at 29,- 
000 feet, being more than five miles of perpendicular altitude. 
The depth of the sea is shown by the line a h, at the extremity 
of the arc. When we consider that the altitude of the highest 
mountains bears so small a proportion to the probable thickness 
of the earth's crust, we will be prepared to admit the possibility 
that they might once have been the bed of the ocean, and may 
have been raised to their present situations by subterranean 
agency, 



EXTENT OF SURFACE. 179 

The external crust, or covering of the earth, is composed of a 
vast amount of substances which we shall more fully describe 
hereafter, but which, under the indefinite but convenient terms 
of rocks and earth, embracing every variety of element, and 
combination, are familiar to every one. Although of such mi- 
croscopic value as regards* the dimensions of the globe itself,- yet 
the crust upon which we are located, is of infinite importance to 
man. With its alternations of land and water, of valleys and 
mountains, it is the seat of vast empires, and the storehouse of 
the wealth of nations. The surface of the earth has been com- 
puted to contain one hundred and fifty millions of square miles, 
about three-fourths of which are covered by seas, and another 
large proportion by bodies of fresh water, by polar ice, and eter- 
nal snows ; so that, taking into the estimate the sterile tracts, the 
forests, the barren mountains, the bogs, morasses, &c, scarcely 
more than one-fifth of the globe is fit for the habitation of man. 
The area of the Pacific ocean alone, is estimated as equal to the 
whole surface of the dry land, hence, if the waters of the globe 
were uniformly distributed over its surface, the inequalities being 
leveled, the whole earth would be covered with water to a depth 
of about three feet. The present arrangement of continents and 
islands cannot therefore be supposed to have always existed, in- 
deed, there is abundant evidence to show that all those parts, 
which we call dry land, have at some very remote period been 
underwater, and that the soil upon which we now tread, is com- 
posed of regular strata, deposited by water. It is but a short period 
since the utmost ignorance prevailed as to the structure of the 
planet which we inhabit. It was accustomed to be looked upon 
as a mass of confusion, the chaos of old, where, in incongruous 
masses, were heaped the various substances of which it was 
composed, and where antagonistic forces were striving confusedly 
together. 

It was true that rocks were found at some places upon the sur- 
face, and not at others, but this was regarded as mere matter of 
chance, no one supposed any order, or any definite arrangement, 
It was reserved for modern science to show that the crust of the 
earth from its surface downwards, is composed of regular stra- 



TOU THE WORLD. 

! ta, always succeeding in the same order wherever examined, and 
each formation mark ing a distinct epoch in the history of our 
planet; each characterized by its own flora and fanna, so that the 
whole substance which has hitherto been explored, consists of 
either minerals, i. e. inorganic substances formed by natural ope- 
rations, or the fossil remains of animals and vegetables, charac- 
terizing peculiar and distinct epochs in the history of the globe. 
'" The arrangement of the various-formations may be represented 
by an alphabetical series from a to z, and this order, though it is 
frequently imperfect, is never inverted. We often miss one, or 
more, terms in the series, and lose, say the b or h or m, or even 
several letters in succession, but we never find the b taking the 
place of the a, or d preceding the c, or any member of the series 
usurping the position of another which ought to go before it ; in 
other terms, we never meet with the entire series of deposits, but 
vthose which do occur invariably follow in a regular order of se- 
quence.' ' 

We have said that these strata are all either mineral or fossil. 
■Remotely they all are of mineral origin, for all organic substances 
have been at some time elaborated from inorganic matter by that 
marvelous principle termed vitality. There are fourteen simple 
substances which are named below in order, according to their 
importance, which constitute the chief part of the earth's sur- 
face. The first eight are called simple No?i- Metallic substances, 

1. Oxj r gen, 5. Sulphur, 

2. Hydrogen, 6. Chlorine, 

3. Nitrogen, 7. Fluorine, 

4. Carbon, 8. Phosphorus. 

These eight simple substances by their union with certain metals, 
which are hence called metallic bases, and also by union with 
each other, form by far the greatest amount of all the matter, or- 
ganic, or inorganic, solid, or liquid, or gasseous, which- is known 
to exist on the surface of the earth. The metallic bases alluded 
?t0 are 

1. Siliciurn, 4. Sodium, 

2. Aluminium, 5. Magnesium, 

3. Potassium, 6. Calcium. 

We cannot here describe each of these elementarv bodies, this 



METALLIC SflN'fcRALS, 181 

Will be found in. most treatises upon chemistry; suffice it that a 
union of silicium and oxygen forms nearly one half the solid part 
of the earth's crust, being a chief ingredient in all the principal 
rocks. It appears nearly pure in the state of transparent rock 
crystal, and is the chief ingredient of our ordinary flints and 
sands. Aluminium in combination with oxygen, is the ba.se of 
the various clays alid clayey slates. Potassium in combination 
with oxygen, and also sodium with oxygen, constitute very im- 
portant ingredients of the rocks and earths under the well known 
forms of potash and soda, and the latter in combination with 
chlorine forms muriate of soda or common salt, so widely preva- 
lent in the ocean, and in beds of rock salt. Magnesium is the 
base of manganese a chief ingredient of the chalks, and magne- 
sian limestones; and calcium is the metallic base of lime, and is 
found In abundance in the various limestones and gypsums. Be- 
sides the simple substances named, we have the metallic miner- 
als, which are usually found in beds or veins. The most of these 
are so well known that they are recognised at a glance. Iron is 
the most useful and most abundant, when combined with sulphur 
it crystalises in cubes, is of a bright yellow, and is often mista- 
ken for gold; this variety is termed iron pyrites. Iron is likewise 
found in combination with oxygen and carbon, and occasionally 
nearly pure. Lead is a well known metal occurring principally 
in union with sulphur, under the form called galena, in cubic 
crystals. Copper is found in combination with oxygen and sul- 
phur, and also native, or pure ; in combination with carbon and 
oxygen it assumes beautiful tints of blue and green. Tin, zinc, 
and manganese are too well known to need any particular descrip- 
tion here. It is said that tin is only found in the primitive or 
lowest order of rocks, and that the tin mines of Cornwall extend 
many hundred feet under the-sea, and that the noise of the waves 
and the rolling of the pebbles can be distinctly heard. We need 
not describe the precious metals, silver, gold, and platina, as 
everybody is familiar with their general properties. The various 
substances which form the crust of the earth, and which have 
been investigated by the persevering energy of man, are arranged 
into two great classes, which embrace all the various soils, sandg, 
i 



182 the woitov 

gravels, clays, limestones, coals, slates, and granites ; tfiese ttoti 
classes, are the stratified, and unstratified rocks. In the former, 
are included those portions of the crust of the earth which ex-> 
hibit a sedimentary character, i. t.* evidence of deposition through 
the agency of water. It is supposed that all rocks were once de- 
posited in this manner, but that the present crystaline form of 
some of them is owing to heat, hence the unstratified, are some- 
times termed the igneous or the plutonic rocks; and the strata 
which happen to intervene between them, being partly changed 
in their character, yet not wholly so, are termed the metamorphicf 
or transformed rocks; and those rocks resembling lavas scoriae, 
and other substances, emitted by burning mountains, still in ac-* 
tivity, are called volcanic. When we assume that ail the igneous 
or plutonic rocks, such as granite, sienite, and the like, are of 
sedimentary origin, we speak hypothetically, they are supposed 
to be so ; for rocks, which are well known to present evidence of 
aqueous origin, become crystaline, and lose the marks of stratifi- 
cation under pressure, and by the influence of heat ; thus, chalk 
has been converted into marble. Sir James Hall, exposed pound- 
ed chalk to intense heat, under great pressure, and it was fused, 
not into lime, but into crystaline marble ; even the shells inclosed 
in the chalk underwent the same transmutation, yet preserved 
their forms; and where ancient streams of lava have traversed 
chalk, the latter invariably possesses a crystaline structure, and a 
series of changes from a loose earthy deposit, to compact volcanic 
lava, may be traced in numerous instances, so as to leave no 
doubt of the former aqueous origin, and the sedimentary deposit. 

The crystaline rocks, such as granite, sienite, porphyry, ser- 
pentine* and greenstone, are generally termed the ancient or 
earliest rocks, as they are uniformly found underlying all the 
other strata ; they were hence, named hypogene, under-lying, by 
Mr. Lyell. It is now however, ascertained that they belong to no 
particular age or epoch, exclusively ; for granite is found occur- 
ring at comparatively modern, as well as ancient epochs, over- 
laying the other strata precisely in the same manner as masses 
of volcanic rock recently ejected, spread out upon the soil below. 
The difference in character between the modern lavae, and 



3 I RATIFIED ROCKS- 



183 



the lower igneous rocks, is doubtless to be attributed to their for- 
mation upon the surface, instead of under pressure* The term 
hypogene includes the plutonic, and metamorphic rocks. 

The sedimentary rocks are termed fossiliferous, or fossil-bear = 
ing, in distinction to the igneous, or plutonic rocks, in which, by 
the action of heat, all fossil remains are wanting* The stratified 
rocks were originally deposited in a horizontal position as repre- 
sented in this engraving, but they are rarely seen perfectly hori- 




zontal, hence, it is inferred, that subsequently to their deposition, 
they have been subjected to a variety of disturbing causes, by 
which they have been made to assume all inclinations to the 
horizon. Occasionally they are uplifted to an almost vertical po- 
sition, as in the following illustration, exhibiting the strata on 
which Powis Castle is built: when by being thus upheaved, the 




edges of the strata are denuded, or uncovered, they are said to 
crop out, when this occurs, it will be found that the strata suc- 
ceed each other in regular order, as we have already mentioned. 
When strata crop out, it is apparent, that having been elevated by 






184 



THE WOftU). 



some internal agency, the various formations^ or beds of nearly 
the same character, will occur in contrary order, thus, suppose 
that by an upheaving cause, a series of strata, fig. 1, lying orig- 




=»|y^ife 







inally horizontal, as deposited at successive epochs, by water, to 
be, by some internal force, upheaved as in fig. 2, the external 




*&2 

surface being rent and cracked, and further that after a course of 
ages, the softer and more modern deposits should be worn away 
by the agency of rains, frosts, floods, &c. t until it was reduced to 
the level a b, we would have the succession of strata as in fig. 3, 




%3 

the harder rocks, perhaps of granite, forming a nucleus, or cen«" 
tre, around which the rest would lie in order; perfectly circular if 
the elevation had been a true mound, or arranged in lines parallel, 
or curved, according to the nature of the original elevation, and 
if the elevation and subsequent denudation, had occured at a very 
remote period, the whole might be covered with a light loose soil. 
A very pretty and instructive example is shown in the diagram 
on the next page, which is an outline map of Michigan. 

Here the centre of the state is occupied by the coal measures 
or formation, shown by the shaded portions, skirting this i a nar- 
row stratum of limestone, beyond this and circling around it, is a 



SUCCESSION OF STRATA. 



185 



wide stratum of the sandstone formation, followed by a foimation 
of marine limestone and shales and slate. It is by observations 




thus made near, or upon the surface, and carefully compared by 
means of the fossils which are found imbeded in them, that ge- 
ologists classify the various groups in the order we shall presently 
name, and, as each stratum is characterized by its peculiar fossils, 
and is never found taking the precedence of another which may 
be anywhere found before it, they are justly supposed to be the 
productions of different epochs. Thus, at one period of the earth's 
history, peculiar limestones, sandstones, marls, and clays, were 
deposited over the whole globe, upon those portions covered by 
water; in which the zoophytes, fishes, drifted wood, plants, rep- 
tiles &c, characteristic of that epoch were imbedded. At an- 
other and previous period, were deposited the shales, the mill- 
stone grit, and the immense beds of coal, imbedding peculiar and 
distinct remains of animals and vegetables characteristic of that 
epoch. At a still earlier period we find other distinct sedimentary 
rocks, and under the whole, although sometimes appearing on the 



186 THE WORLD, 

surface, by being upheaved and uncovered, are found the crysta- 
line masses of granite, porphyry, and sienite. Above all these 
well marked sedimentary, or water deposits, lies a vast accumu- 
lation of what is termed drift, being water worn, transported ma- 
terials, consisting of the ruins of older rocks, and forming our 
light covering soil, sometimes scarcely overlaying, and at others 
of many feet in thickness, principally sand, clay, and gravel, and 
large masses of water worn or rounded stones, called boulders. 
The more recent deposit of this sort is called Alluvium, and in it 
are imbedded the remains of man and his works, and such is the 
character of the fluviatile or river deposits now going on, and to 
which we shall again allude. The older deposit is termed Dilu^ 
vium, and is found to contain no traces of man or his works, but 
in it are imbededthe remains of huge animals and reptiles now 
extinct, and also with them the bones of many existing species of 
animals, and the fossil remains of many known species of plants 
are found. In the following chapter we shall endeavor to give a 
clear view of the succession of the various strata and a short de- 
scription of each, which shall be intelligible to any one who may 
feel enough interested to read it, and in concluding this chapter 
we must be allowed to say, that if the present part of our work 
does not interest the reader, the book may as well be closed ; we 
can learn him nothing, for there is no sympathy between us, 



CHRONOLOGICAL ARRANGEMENT OF STRATA 187 



CHAPTER II. 

Chronological Arrangement of Strata. 

*'Whai once had been the" solid earth, I saw 
To be a strait ; and from the waves new lands 
Arose. Far off from the resounding" sea, 
The shells were strown about." Odd, 

Although geologists are perfectly agreed as to the order of suc- 
cession of the various strata, yet they have different methods of 
expressing the same fact. In other words, the names which are 
tised to designate the different formations vary somewhat, but in 
the great leading features all are agreed. Thus, it matters little, 
whether, after having divided all rocks into two great classes, 
fossiliferous, and non-fossiliferous or metamorphic, we subdivide 
the former with Dr. Buckland, into alluvium, diluvium, tertiary, 
and the secondary or transition series; or with Dr. Mantell, into 
modern and ancient alluvium, tertiary strata, and secondary for- 
mations; both include the same classes of rocks; or whether we 
name a certain order of rocks the saliferous strata, or the upper 
and lower red sandstone; both mean the same thing. The classi- 
fication which we have adopted is principally that of Dr. Man- 
tell, who gives the following as the chronological arrangement of 
the strata, commencing with the uppermost or newest deposits, 

I. FOSSILIFEROUS STRATA. 

1. Modern and Ancient Alluvium. — Comprising the modern 
and superficial deposits of waterworn and transported materials, 
sometimes called drift, and consisting of gravel, boulders, sand, 
<clay, <fcc. The modern deposits are characterized by the remains 
of man, and contemporaneous animals and plants. The ancient, 
sometimes called Diluvium, by an immense proportion of large 



188 THE WORLB^. 

mammalia and camivora of species and genera, both recent anc^ 
extinct. 

2. The Tertiary System. — An extensive series comprising 
many isolated groups of marine, and lacustrine, or lake formed 
deposits, characterized by the remains of animals and vegetables^ 
the greater portion of which are extinct. Volcanoes of great ex- 
tent were in activity during this epoch.. Mr. Lyell subdivides 
this series into the pliocene, or more recent; the miocene, less re- 
cent; and the eocene, dawn of recent;, according to the percentage 
of recent shells contained in each. 

Secondary Formations, 

3. The Chale: or Cretaceous System. — A marine formation , 
being the bed of an ancient sea, comprising limestones, sand- 
stones, marls, and clays, and abounding in the remains of zoophy- 
tes, molusca, cephalapoda, fishes &c, drifted wood, and marine 
plants, with crocodiles, turtles and other, now extinct reptiles* 
also birds. 

The chalk formation embraces several beds or distinct strata* 
thus, we have the upper chalk with flints, and the lower without; 
the chalk marl, the firestone, the gait or stiff blue, or black clay, 
abounding in shells, the shanklin or green sand. 

4. The Wealden. — From the German icald, a wood, Ik* 
whole tract so called in England having been once a dense forest. 
This formation is the only known secondary fluviatile, or river 
formed deposit. It is a fresh water formation, evidently the de- 
posit of some enormous ancient rivers, its fossil remains being 
the spoils of river and land,, it is characterized by the remains o£ 
enormous and peculiar reptiles, namely the iguanodon, hylaeosa- 
rus, megalosaurus, plesiosaurus, crocodile, turtle, &c; of ter- 
restrial plants, fresh water shell-fish, and birds.. The group 
called the Wealden is composed of beds of stiff blue clay, with 
beds of shelly limestone, called Sussex marble, beds of sands and 
sandstones as found at Hastings in England, and the clays, sand- 
stones, and shelly limestones,, as found ife the Isle of Purbeek* 
called Purbeck marble*. 



SUCCESSION OF STRATA. 189 

5. The Oolite. — This is a marine formation of vast extent 
and thickness, its name means egg stone, because, it is formed 
of small egg like grains. It consists of limestones and clays, 
which abound in marine shells, corals, fishes; reptiles, both ter- 
restrial and marine; land plants of peculiar species, and the re- 
mains of two or more genera of marsupial animals, are likewise 
found in it. 

6. The Lias. — This name is supposed to be a provincial cor- 
ruption of the word layers, as it consists of shale, or indurated 
slaty clay, which splits into layers, alternating with clays and 
limestones, containing marine shells, cephalapoda, crinoidea and 
fishes. It is chiefly remarkable however, for its remains of 
enormous reptiles particularly the plesiosaurus and the ichthyos- 
aurus. The Lias group consists of the upper lias shale, mixed 
with the lower oolite, containing saurian remains, belemnites and 
ammonites ; the lias marls; calcareous, sandy, and ferruginous; 
the lower lias clay and shales intercalated with sands and sep- 
taria, and lastly a series of laminated limestones, with partings of 
clay, which change into vast beds of red marl and sandstone 
forming, 

7. Xhe Saliferous, or New Red Sandstone System. — A 
marine formation comprising variegated marls and sandstones, 
and conglomerates, frequently of a red color. The name new is 
given to distinguish it from a formation of the same mineralogical 
character but much older. This series of deposits is remarkable 
for the traces or footsteps of marsupial animals and birds, and 
contains fossil remains of marine and terrestrial plants, fishes and 
reptiles. This series forms the grand depository of rock-salt and 
lime, hence called the saliferous, salt bearing. Its variegated 
color is owing to oxide of iron. The series consists of the upper 
new red sandstone, containing gypsum and rock salt, with varie- 
gated red and white sandstones, conglomerates or detritus of 
older rocks cemented together, and the lower new red sandstone, 
consisting of magnesian limestones called dolomite, and marls 
and conglomerates colored with oxide of iron. This series rests 
upon, 



190 THE WORLD. 

8. The Carboniferous, or Coal System, which is formed of 
sandstones, grits, shales, layers of ironstone, and clay; with 
immense beds of coal; fresh water limestone sparingly, and ma- 
rine limestone abundantly. This system is characterized by in- 
numerable remains of land and aquatic plants, of a tropical char- 
acter, and belonging to extinct species and genera, with fishes, 
reptiles, and insects. The series includes the coal measures, 
which are sandstone, and shale, with numerous layers of coal, 
containing land plants in profusion. Limestones, with fresh water 
and marine shells, Millstone grit, which consists of sandstone 
and shale, with thin seams of coal, and quartose conglomerates 
sometimes used for millstones. The carboniferous or mountain 
limestone, consisting of limestone and flagstone, abounding in 
crinoidea, and marine shells, yielding several varieties of black, 
blueish grey, and variegated marbles. The*coal bearing strata of 
this country differ some from the European. The seams of coal 
appear however, even in Europe, to be veiy unequally distributed; 
although the great coal formation belongs in the order where we 
have placed it, yet seams of anthracite coal are found in almost 
every rock from the lias, to the upper metamorphic rocks, show- 
ing that the coal beds have occurred at very unequal intervals, 
hence their formation may be of any date between the*new and 
the old red sandstone. 

9. The Devonian, or Old Red Sandstone System. — This 
name is derived from the English locality, where it is most large- 
ly developed, viz : Devonshire. It is a marine deposit, chiefly 
remarkatye for its extraordinary forms of fossil fish. This sys- 
tem is composed of various strata, flagstones, conglomerates, 
quartose grits, sandstones, marls, and limestones ; the prevailing 
color of all these is a dark red. But few fossils are found in the 
sandstone and conglomerates, but in the marls, and concretionary 
limestones, sometimes called corn -stones, peculiar genera of fish, 
and many species of marine shells are found. This system lies 
immediately below the mountain limestone. The sandstones are 
in various stages of induration, and when slaty are employed for 
roofing. The red color is derived from peroxide of iron. The 
formation of these rocks, has manifestly resulted from the waste 



SUCCESSION OF STRATA. 19 1 

of slate rocks, their detritus being cemented together by red sand, 
or marl, into coarse conglomerates. 

Primary Foss'diferous Period. 

10. The Silurian System. — This name is derived from silures, 
the name of the ancient Britons who inhabited that part of Eng- 
land where it is most developed, viz : the border counties of 
England and Wales, and south Wales. It is a marine deposit of 
vast extent and importance, containing a great abundance of or<- 
ganic remains. It is principally composed of marine limestone, 
shales, sandstones, and calcareous flags, abounding in shells, 
corals, trilobites, and crinoidea of peculiar types; but few vegeta- 
ble remains are found below the old red sandstone. 

.pe- 
ll. The Cambrian, or Grauwacke System. — Grauwacke is 

a coarse slaty rock, Containing fragments of other rocks, some- 
times passing into the common clay slate, and sometimes, when 
the fragments are very numerous and small, into sandstones and 
grits; it contains a few shells and corals, and occasionally im- 
pressions of fuci; with this system all traces of organic remains 
disappear. The fineness of grain, general aspect, and character 
of these rocks, are well known from the universal employment 
of slate for economic purposes. 

II. HYPOGENE OR METAMORPHIC ROCKS. 

DestitiUe of Organic Remains. 

stratified. 

12. The Mica Schist. — This formation is supposed from cer- 
tain traces of stratification, to have been sedimentary in its origin, 
but subsequently altered by the influence of heat. It consists of 
mica slate, granite rock, crystaline limestone, or white marble, 
and hornblende schist, exhibiting no traces of organic remains. 

13. The Gneiss System. — Layers of gneiss, sienite, and quartz 
rock, alternating with clay slate, andjmica schist, but still exhib- 
iting marks of former stratification. 

unstratified. 
14. Granitic System. — Consisting of porphyry, serpentina, 
and trap rock in shapeless masses, and in dykes and veins 



192 THE WORI,J>., 

15. Volcanic Rocks. — These are the products of fire, or sub- 
terraneous heat, ejected from beneath the surface, through fis- 
sures in the earth's crust, both in ancient and modern times. 
The erupted materials of the ancient volcanoes being trap, basalt, 
loadstone and tuff, and the products of recent sub- ©rial volcanoes, 
lava, scoriae,, pumice and ashes. 

The general proportionate' thickness of each of these several 
deposits has been estimated as under, but tbe statement must b^ 
regarded as a mere approximation. 

Tertiary System 2,000 feet. 

Cretaceous, 1,000 " 

Weald, 1,000 •« 

Oolite and Lias, 2,500 " 

Saliferous 2,000 * 

•> Carboniferous, 10,000 " 

Old Red Sandstone, 10,000 «« 

Silurian, \7,500 * 

- Cambrian, 30,000 " 

Mica Schist, and Gneiss, not ascertained, but far exceeding that 
of any of the superposed deposits. 

We have now given a connected view of the order of suc- 
cession of the several strata, each characterised by its peculiar 
animals and plants. All these are marine deposits except one, 
the fourth, called the Wealden. This is a fresh water formation, 
and is the deposit of a mighty ancient river, or of several of them, 
and its organic remains are such as might be expected to result 
from the sediment of such a river, consisting of plants, shells, 
fish, and reptiles, imbedded in the mud together. It is almost 
the only evidence which remains of the ancient land, showing 
that while the immense deposits were going on in the bed of 
the ocean, here were bodies of fresh water, rolling over a vast 
extent of land, bearing upon their waters the remains of trees, 
and huge reptiles. In the following chapters we shall consider 
each of these formations more fully, and describe more particu- 
larly some of the fossils found in them. It will be observed by 
the careful reader, that most of the marine deposits of the several 
epochs have the same mineralogical character: if we except the 
coal, we will find the rest alternating with marls, clays, lime- 
stones, and sandstones ; each being formed from the ruins of 



GEOLOGICAL NOMENCLATURE. 193 

more ancient formations, and each, imbedding in its sediment 
the characteristic shells, fishes, reptiles, and plants, which were 
either washed into, or once lived in the ancient sea, of which it 
formed the bed. 

The names which have been given to the different geological 
formations must be received with some caution, for they are not 
always indicative of formations fdentical with those from which 
the name was derived. Many of these names are borrowed from 
places; thus, we read of the Jura limestone, the Kimmeredge 
clay, Oxford clay, Purbeck marble, Portland rock, and Potsdam % 
sandstone. These names, referring to the stratum of a known 
locality, were good so far as an identity with that stratum can 
be traced, but from the nature of the case, this is often incom- 
pletely done, and hence the names necessarily cease to be defi- 
nite. Many of the English provincial names are still retained, 
though very uncouth and harsh sounding, thus Geologists often 
employ the terms Cornbrash, Lias, Gault, Coral Rag, and many 
others which have no systematic signification. 

Descriptive names applied in Geology are also defective, and 
when employed, no scrupulous regard must be had to their appro- 
priateness. *' The Green Sand may be white, brown, or red ; 
the Mountain Limestone may occur only in valleys ; the Oolite 
may have no roe-like, structure ; and yet these may be excellent 
geological names, if they be applied to formations, geologically 
identical with those which the phrases originally designated.' * 
The term Oolite is an instance where a descriptive word has be- 
come permanent, and in like manner the term proposed by Mr. 
Murchison, for the transition series of rocks, which, from being 
distinctly marked in South Wales, he calls Silurian, from the 
name of the ancient inhabitants, is in many respects excellent. 
The terms employed by Mr. Lyell, before mentioned, as divisions 
of the Tertiary formation, viz : Pliocene, Miocene, and Eocene, 
according to the percentage of recent shells, being founded upon 
a more natural distinction will undoubtedly come into general use, 
but even these are to be used with caution, and not allowed to set 
aside the indications drawn from the natural relations of the strata, 



194 



THE WORLD. 




CHRONOLOGICAL ARRANGEMENT OF STRATA. 



195 



EXPLANATION. 

Ideal section of the crust of the earth, showing the chronologi- 
cal arrangement of the strata. 

M— Mantell. 

B — Buckland. 
- L— Lyell. 



1. Alluvial or modern deposits. 

2. Tertiary formations. 

3. Cretaceous system, compris- 
ing the chalk, with & with- 
out flints, chalk marl, gait 
or blue clay, Shanklin sand. 

4. TheWealden. 

5. The Oolite. 

6. The Lias. 

7. The Saliferous, consisting of 
New Red Sandstone, Mag- 
nesian Limestone. 

8. The Carboniferous System, 
namely, the Coal measures, 
the Mountain limestone. 

. 9. The Devonian, or Old Red 
Sandstone. 

10. The Silurian, consisting of 
marine limestones, shales, 
calcareous flags. 

11. The Cambrian. 

12. Mica Schist. 

13. The Gneiss. 

14. Granitic System. 

15. Volcanic Rock. 

a. 1. Dyke of Porphyry in gran- 
ite, passing through & over- 
laying gneiss. 



a. 2. do. do. Overlaying the coal 

formation. 

b. 1. Granite veins in Granite, 
b. 2. do. do. passing through por- 

pltyry, gneiss, & mica schist. 

b. 3. do. do. Overlaying Grau- 

wacke. 

c. Dyke of Trap, passing thro' 

grauwacke^and the lamina- 
tions of marine limestones, 
forming basaltic columns. 

c. 1. do. do. intersecting, and 
overlaying an older dyke of 
porphyry. 

c. \£ do. do. overlaying the oolite 
system, 

c. 3. do. do. overlaying the chalk 

being lava of the extinct 
volcanoes of the Tertiary 
period. 

d. Modern lava. 

e. Cave in magnesian limestone. 

f. Metallic veins in granite. 

g. Extinct volcano, 
h. Az*tesian well. 






196 THE WORLD. 

The order of succession which we have given has been de- 
termined by a series of the most patient investigations, and from 
an immense accumulation of facts, collected by able observers in 
all parts of the globe. On page 194 we have given a diagram 
showing their order. It will be perceived that some parts of the 
representation are necessarily exaggerated. Commencing at the 
left we have the hypogene, or underlying rocks, unstratified and 
stratified ; then the primary and secondary fossiliferous, and also 
the tertiary, lastly the volcanic. The alluvium we have placed 
in various situations, overlaying the older rocks. 



AQUEOUS CAUSES OF CHANGE, 197 



CHAPTER III. 

Aqueous Causes of Change, 

44 The rivers swell, 
Of bonds impatient. Sudden from the hills, 
O'er rocks and woods, in broad, brown cataracts, 
A thousand snow-fed torrents shoot at once ; 
And where they rush, the wide resounding plain 
Is left one slimy waste." Thomson. 

Is the preceding chapter we have given a general view of the 
arrangement of the strata which compose the crust of the earth, 
We now proceed to consider the changes at present going on in 
the organic and inorganic kingdoms of nature. We will thus be 
better prepared to admit that the fossil remains which occur 
everywhere in the stratified rocks, and that the stratification of 
those rocks, are results of laws now in full operation, but exerted 
through a period of years, it would be utterly vain to attempt to 
estimate. In the present chapter, which presents us with a sub- 
ject which of itself might f rm a volume, we can only hastily 
glance, at some of the most active causes of change now in ope=- 
ration, those who desire to learn more will find ample informa- 
tion in the writings of Lyell, Mantell, Buckland, and other well 
known geologists. 

Although from the very nature of the case, geology is some- 
what a speculative science, since it takes into consideration the 
changes and vicissitudes which the earth has undergone, during 
aores so remote, that the mind can with difficulty conceive of the 
lapse of time past, and endeavors to explain them by the appliea° 
lion of laws now in action, but whose silent operation is unheeded 
by the great mass, yet it at the same time presents us with the 
noblest views of the material universe: and the philosophic mind, 
in reviewing ever so cursorily, the traces of the past, cannot fail 
to he struck with the harmony of the material world. Everything 



198 THE WORLD. 

around us is in a most active state of change, literally speaking 
there is no such thing as rest. Every operation of nature, how- 
ever minute and familiar, the heat and the cold, the moisture and 
the drouth, the warmth of summer and the frosts of winter, the 
snow and the ice, nay, every drop of rain that falls from the at- 
mosphere, performs its share in displacing and renewing the solid 
crust of the earth, and contributes its alloted portion in carrying 
on the great work of universal metamorphosis and change. The 
great agents of change in the inorganic world may be divided 
into two classes, the aqueous and the igneous. To the aqueous 
belong rivers, torrents, springs, currents, and tides ; to the ig- 
neous volcanoes and earthquakes. Beside these we may enu- 
merate the agency of the atmosphere, which is partly mechani- 
cal, and partly chemical; and vital action. We shall consider 
these several agents of change in order, and see their present 
eifect in changing the sea to land, and land to sea; in excavating 
valleys and destroying hills ; in the transition of dry ground to 
marshes, and the reverse ; the occurrence of earthquakes and 
their phenomena; the uniting of islands with main lands, and 
insulation of peninsulas. 

In this manner, although we may not be able to comprehend en- 
tirely the degrading and elevating causes above enumerated, yet 
we will see abundant means for the conversion of the soil upon 
which we now tread, from the bed of an ocean to dry land; we 
shall see how wood has been changed into stone, and plants and 
fishes imbedded in solid rock. We shall first consider the action 
of running water. The heated atmosphere which sweeps over 
the vast ocean and the surface of the earth, absorbs and carries 
with it an immense amount of aqueous vapor, to be again de- 
posited when the air is cooled, in the form of clouds, mist or rain. 
A large amount of this moisture is deposited upon mountains and 
elevated lands, and thus the more elevated regions become per- 
petual reservoirs of water, which flows down in gentle streams 
and rivers, irrigating the plains below. At the first glance we 
might suppose the amount of water carried up into the air by 
evaporation was of too trifling a nature to be instrumental in ef- 
fecting any great mechanical change, but a moments reflection 



ACTION OF RUNNING WATER. 199 

will convince us that the amount is almost beyond estimate. All 
the rivers on the face of the earth are constantly pouring their 
waters into the sea, and yet its level is not affected in the slight- 
est degree, hence we infer that the quantity of mositure evapo- 
rated from the surface is exactly equal to the sum of all the rivers 
of the world. If the evaporation and restoration of the waters 
were all the effect which is produced by the agencies just de- 
scribed, little change would be accomplished upon the face of the 
country over which the waters might flow in their passage to the 
sea. But in the more elevated tracts of country, the atmosphere 
acts powerfully upon the soil, a :d by the influence of heat and 
cold, by dampness and dryness, and of frost and rain, loosens the 
most coherent masses and disintegrates the solid rocks. The 
mountain streams flow down more or less charged with earthy 
matter, worn from the soil and rocks over which they flow. In 
their passages toward the sea, sometimes over an immense tract 
of country, they often unite and pour their waters along with al- 
most irresistible fury. The solvent power of the water assists 
very materially in degrading the rocky channels through which 
it flows, and acts powerfully on the alkaline and calcareous ele- 
ments of the soil, and especially when it holds carbonic acid in 
solution, which is almost always the case. When the earthy mat- 
ter and pebbles are thus intermingled with running water, a new 
mechanical power is gained, by the attrition as they are borne 
along, thus sapping and gradually undermining high banks and 
rocks, until at length the overhanging mass is precipitated into 
the current and swept away by its waters. In this manner, islands 
are cut off from the main lands, and shoals, and rich earthy de- 
posits called deltas are formed at the mouths of rivers. There is 
nothing so very remarkable in the power of currents to transport 
even heavy masses of stone, for we must remember that the spe- 
cific gravity of water is much greater than air, and a stone im- 
mersed in a stream will loose about half its weight, and many of 
the lighter particles of the soil will almost float. 

Sir George Staunton estimated that the quantity of sediment 
borne down by the Yellow River in China, in a single day, was 
equal to forty-eight millions of cubic feet, and late observations 



200 THE WORLD. 

upon the Ganges, at the time of its flood, or in the rainy season, 
when it is fully charged with sediment, shows that it discharges 
6,082,041,600 cubic feet in 122 days, and during the three months 
of hot weather, and the five months winter, it discharges 286,- 
035,840 cubic feet more, a quantity small compared with the for- 
mer, the total annual discharge is therefore 6,368,077,440 cubic 
feet 

"In order" says Mr, Lyell, "to give some idea of the magni- 
tude of this result, we will assume that the specific gravity of the 
dried mud, is only one-half that of granite (it would, however, 
be more), in that case the earthy matter discharged in a year, 
would equal 3,184,038,720 cubic feet of granite. Now, about 
12J cubic feet of granite weigh one ton, and it is computed that 
the great Pyramid of Egypt, if it were a solid mass of granite, 
would weigh about 6,000,000 tons. The mass of matter there- 
fore carried down annually, would, according to this estimate, 
more than equal in weight and bulk forty-two of the great pyra- 
mids of Egypt, and that borne down in four months of the rains, 
would equal forty pyramids. The base of the great Pyramid of 
Egypt covers eleven acres, and its perpendicular height is about 
five hundred feet. It is scarcely possible to present any picture 
to the miner which will convey an adequate conception of the 
mighty scale of this operation, so tranquilly and almost insensi- 
bly carried on by the Ganges, * It may however, be stated, that if 
a fleet of more than eighty Indiamen, each freighted with about 
1400 tons weight of mud, were to sail down the river every hour 
of every day and night for four months continually, they would 
only transport from the higher country to the sea, a mass of solid 
matter equal to that borne down by the Ganges in the flood sea- 
son." 

The same effect is observable in the mighty rivers of America. 
The Mississippi annually bears down upon its swollen stream in- 
numerable quantities of trees and sediment, which are imbedded 
in the basin of the sea at the mouth of the river. In this manner 
the remains of animals and vegetables are being continually en- 
veloped, and, should these deltas some day become dryland, the 
naturalist could determine bv a studv of the imbedded remains, 



EXCAVATION OF A LAVA CLRR£>T. 201 

ihe character of the country through which the stream had flowed. 
Below we give a diagram showing the excavation of a lava cur- 
rent by the action of the river Simento, one of the largest of the 




Sicilian rivers, which flows at the base of Etna. A A, bed of lava 
which has flown to a distance of five or six miles; B, bed of the 
Simento; C, foot of the cone of Etna; D, marine and volcanic 
strata: E, ancient bed of the river. The lava current in which 
the channel is eroded is one of the more recent, having been 
ejected in 1603. In a little more than two centuries the Simento 
has worn a passage from fifty, to several hundred feet wide, and 
in some parts from forty to fifty feet deep. The portion of lava 
cut through, is not porous, or mixed with cinders and scoria, but 
consists of a compact homogeneous mass of hard blue rock. The 
Falls of Niagara afford a magnificent example of the progressive 
excavation of a deep valley in solid rock. It appears from exami- 
nation that the Falls were once at Queenstown, about seven miles 
below their present position. It is possible however that a natural 
chasm may have previously been formed a part of this distance, 
which the river has since widened, although a careful study of 
the face of the country, and also the existing proofs, at various 
places, several miles below the present falls, of fluvatile depos::-. 
seem to show conclusively that the falls have gradually receded 
from near the present site of Lewiston and Queenstown. 

When by the melting of snows and ice, an unusual amount of 
water is accumulated at some high point, and the barriers which 
have been restraining it give way suddenly, the flood sweeps on- 
ward with a fury which overcomes every obstacle. Such was the 
flood in the valley of Bagnes, described by Mr. Lyell, in his Prin- 
ciples of Geology. The bed of the river Dranse being blocked 



20*2 Ttiis woRLfr. 

up by the avalanches of snow and ice, a reservoir or lake, was 
thus formed, about half a league in length, two hundred feet deep* 
and seven hundred feet wide; To lessen the mischief appre* 
hended from the sudden bursting of this ice barrier, a channel 
was cut through the ice about 700 feet in length ; the flow of the 
waters deepened this channel until nearly half the contents of 
the lake were drained off, but on the approach of the hot season* 
the remaining mass gave way with a tremendous crash, and the 
residue of the lake was emptied in half an hour. As the mass 
of waters and floating ice swept through the narrow gorges, it 
rose sometimes to an immense height, to burst again with in- 
creased fury into the next basin, sweeping along rocks, forests* 
bridges, and cultivated lands. Immense fragments of granite 
rock were torn from the ancient soil and borne down ; one of 
these, was sixty paces in circumference* 

The Deltas, or triangular sedimentary deposits which are formed 
at the mouths of large rivers, often exhibit distinct marks of strati ^ 
fication, and when they terminate in an extensive estuary, or arm 
of the sea, the layer of mud brought down by the river is regu- 
larly covered by a layer of sand, borne in and deposited upon the 
mud at each returning tide. It is in this manner that the ripple 
marks, and tracks of vermes, and molusces, are preserved. Every 
one must have noticed, in walking along a sandy shore, at low 
water, the undulating surface of the mud or sand, caused by the 
little ripples in the water, and also the varied tracks of worms, 
shell-fish, and birds. When a thin layer of mud happens to be 
deposited over these before the next return of the waves, a perfect 
cast is thus obtained. Mr. Lyell, in his travels in North America 
mentions that he had obtained at Wolfville, on the Bay of Fundy, 
thin slabs of the dried red mud, which presented peifect impres- 
sions, on the upper side, showing the recent foot-prints of a small 
sandpiper, as it marched over the soft mud, which had after- 
wards so much hardened in the sun as to become consolidated, 
and upon the under surface exhibiting a cast of the impressions 
made in a previous deposit. The red sediment, or mud deposited 
by the waters of the Bay, is obtained from undermining cliffs of 
red sandstone, and soft red marl, and whenever the velocity of the 



^ ILL VIAIILE FORMATIONS. 203 

current is suspended by the rush of the tides, this mud is thrown 
down, and very large, and widely extended tracts, of rich soil* 
have thus been formed, and thousands of acres have been ex- 
cluded from the encroachments of the sea by artificial embank- 
ments. At the time of very low tides, this soft mud is sometimes 
exposed to the sun for several days, and thus becomes sufficiently 
baked or consolidated, to a depth of several inches, to resist the 
flow of water, which soon deposits upon it another thickness of 
mud. We shall see that in a precisely similar manner, footprints, 
of high antiquity, were formed in the strata of new red sand- 
stone of the valiey of the Connecticut, and also in Europe. 

The large rivers which flow from south to north in the northern 
latitudes, having their sources in a much warmer latitude than 
their mouths, become swollen in their progress northward, on 
account of the ice which has not yet been broken up, hence they 
overflow and sweep through the forests of pines and birches, and 
carry away thousands of the uprooted trees* The timber thus 
drifted down is often laden with the earthy deposit around the 
roots, and being deeply sunk in the water, other masses become 
piled upon it until at length becoming water-logged it sinks and 
is imbedded in the strata if there be any forming. "As the trees" 
says Dr. Richardson, "retain their roots, which are often loaded 
with earth and stones, they readily sink, especially when water 
soaked ; and, accumulating in the eddies, form shoals which ul- 
timately augment into islands. A thicket of small w T illows covers 
the new formed island as soon as it appears above the water, and 
their fibrous roots serve to bind the whole firmly together. Sec- 
tions of these islands are annually made by the river, assisted by 
frost, and it is interesting to study the diversity of appearances 
they present, according to their different ages. The trunks of the 
trees gradually decay until they are converted into a blackish 
brown substance, resembling peat, but which still retains more or 
less of the fibrous structure of the wood ; and layers of this often 
alternate with layers of clay and sand, the whole being penetrated 
to the depth of four or five yards or more, by the long fibrous roots 
of the willows." A deposition of this kind, with the aid of a 
little infiltration of bituminous matter, would produce an excellent 



^04 THE WORLD. 

imitation of coal, with vegetable impressions of the willow roots. 
We will close this chapter with a discription of those extensive 
accumulations of vegetable matter called peat bogs. These are 
marshy grounds covered with successive layers or beds of mosses, 
reeds, equisetae, rushes, and other plants which affect a marshy 
soil; but a species of moss called sphagnum palustjx, which has 
the peculiar property of throwing up new shoots in its upper part 
whilst the lower is decaying, forms a great part of the peat bogs 
of Europe. It is said that one-tenth of Ireland is covered by 
these marshy bogs, in which trees are often found standing erect, 
with their roots imbedded in the sub-soil ; thus presenting evi- 
dence of the formation of the bog since the growth of the trees; 
these are generally oaks where the sub-soil is clay, and firs where 
it is sand. The peat bogs of the north of Europe occupy the 
areas of the ancient forests of oak and pine. At the bottom of 
peat bogs, cakes of oxide of iron, termed bog-iron ore are found, 
partly precipitated from mineral waters, and partly from the de- 
caying vegetable masses. 

One of the most remarkable facts connected with the peat bogs, 
is the preservation of the bodies of men and animals for an in- 
definite period of time; in many instances they are converted 
into a peculiar fatty substance, which resembles spermaceti, 
called adipocire. In June 1747, the body of a woman was found 
six feet deep in a peat-moor, in Lincolnshire. The antique san- 
dals on her feet afforded evidence of her having been buried there 
for many ages ; yet her nails, hair, and skin, are described as 
showing hardly any marks of decay. On the estates of the Earl 
of Moria in Ireland, a human body was dug up a foot deep in 
gravel, covered with eleven feet of moss ; the body was com- 
pletely clothed, and the garments seemed all to be made of hair. 
On the confines of England and Scotland, is a flat area, about 
seven miles in circumference, known as the Solway moss. It is 
a boggy ground covered with grass and rushes, presenting a dry 
crust and fair appearance, but it shakes under the least pressure, 
the bottom being unsound and semi-fluid. The adventurous 
passenger, who sometimes in dry seasons, traverses this perilous, 
waste, to save a few miles, picks his cautious way over the rushy 



1?EJLT BOGSc £0$ 

Y&ssocks as they appear before him, for here the soil is firmest. 
If his foot slip, or if he venture to desert this mark of security, it 
is possible he may never be heard of. In 1772 en the 16th of 
December, this moss being filled with water during heavy rains, 
burst, and a stream of black half-consolidated mud began to creep 
over the pla^'n, k overwhelmed some cottages, and covered an 
area ol 400 acres to a depth of fifteen feet. Dr.JJackson men- 
tions 1 hat in the peat bogs of Maine, a substance exactly similar 
to cannel, or anthracite coal, is found amidst the remains of 
rotten logs of Wood, and beaver sticks. It is a true bituminous 
coal, probably formed from the balsam-fir during its long immer- 
sion in the humid peat. 

We have now briefly considered the action of rivers, and run- 
ning waters, their effect in carrying down to the ocean or lake 
avast quantity of sediment, which is finally deposited, and sub- 
quei'tly, either by pressure, or exposure to air consolidated into 
rock ; that large tracts of country called deltas, at the mouths of 
rive is, are in progress of formation, in which are buried the re- 
mains of animals and vegetables, and in which, are preserved 
the tracks of worms, molusces, and birds ; that by collections of 
rafts upon the large rivers, laden with stones, earths, and sands, 
islands are forming, and the materials for future beds of coal 
collecting ; that peat bogs are now growing, and, bursting their 
ban iers, flooding whole tracts of country, and imbedding forests, 
and the habitations of men. By similar actions, exerted at the 
most remote periods, the present strata of the earth's crust 
weie deposited, and the masses of limestones, sandstones, and 
shales, were formed. We are thus irresistably led to the conclu- 
sion, that however remote may have been the date of these for- 
mations, or however deep they may now be buried below the 
present surface, they were once exposed, and over their surface 
living things moved, and upon it lay the wrecks of organic 
mat ter. 

The entire absence of human remains or works of art in the 
anciently formed deposits, and their extreme abundance in mod- 
ern alluvium, is a sufficient proof of the comparatively recent 
•origin of the human race. It cannot be doubted that human re- 



206 THE WOilL£?. 

mains are as capable of resisting decay as the harder parts 0/ 
many inferior animals. Such remains however, except in places 
subject to great change from volcanic action, or the shifting and 
filling up of the ancient channels of rivers, are never discovered. 
The inference is plain, and we are irresistibly led to the conclu- 
sion, that long antecedent to the date of man, the surface of the 
earth teemed with life ; and that it has been subject to mighty 
revolutions, which have, at once swept off its face, whole races of 
its former inhabitants, whose fossilized remains have formed the 
bed of a mighty ocean. It was therefore a splendid boast, thai 
the deeds of the English chivalry at Agincourt made Henry's 
chronicle 



as rich with praise 



As is the ooze and bottom of the deep 
With sunken wreck and sunless treasuries ! 



AQUEOUS CAUSES Of CHANGE '207 



CHAPTER IV. 

Springs. 

" Thou dost wear 
No stain of thy dark birthplace ; gushing up 
From the red mould and slimy roots of earth, 
Thou flashest through the sun." 

Bryant* 

In the present chapter we shall consider another aqueous cause 
of change, springs, or as they have been termed " subterranean 
drainage." Every one is familiar with the fact, that the water 
which is deposited upon the loose soil, easily percolates through 
it, and makes its way downward to a certain depth according to 
the nature of the underlying strata. Whilst it easily penetrates 
through the gravelly, and sandy formations, it is arrested by the 
almost impervious beds of clay, and sometimes collected into 
large sheets of water, which are often subjected to intense press- 
ure, upon tho well known hydraulic principle so often employed 
in the arts under the form of the hydrostatic press. Mr. Lyell 
mentions that the transmission of water is so rapid through the 
loose gravelly soil over which the river Thames flows, and which 
is upon an impervious sub-stratum of clay, that the wells in this 
vicinity alternately ebb and flow, with the tides of the river. It 
is from this cause, that wherever on the side of a hill, strata of 
clay are found below sandy soils, the water oozes out, not indeed 
in a continuous sheet, but, probably from aome slight difference 
in the constitution of the clay, or from natural fissures or cracks, 
in the form of little streams. The effect of such minute streams 
in finally undermining hilly tracts of country is surprising ; con- 
stantly running, they bear out the light sand, and thus the sub- 
terraneous reservoir extends its # surface gradually, until, at length, 
the superincumbent mass gives way, and sliding upon the slip- 
pery clay is precipitated into the valley below. 



208 



THE WOULD-. 



Much light has been thrown upon the theory of springs by the 
boring of what are called "Artesian Wells," so called from hav- 
ing been first made at Artois in France ; they are made by boring 
the earth with a large augur, three or four inches in diameter. If 
a hard rock is met with, it is triturated with an iron rod, and the 
fragments are then easily removed ; as the boring proceeds, tubes 
are introduced to prevent the sides from caving, and also the 
spreading of the water through the soil. In this manner a well 
was bored for Holt's Hotel, in the city of New York ; 126 feet of 
stratified sands, clay, and river mud, were first penetrated before 
reaching the gneiss rock which underlies the island, 500 feet of 
this rock was subsequently bored through, and an abundant sup- 
ply of good water obtained. When a vein of water is struck, 
it often rushes up with great force, rising several feet above the 
surface, affording a constant supply of water. Borings have been 
made in France to a depth of 1200 and even 1500 feel. Occa- 
sional failure is experienced in boring, sometimes on account of 
the geological structure of the country, and often from the exis- 
tence of subterranean outlets for the water. The following dia- 
gram is from Mr. Lyell, and will illustrate the principle of the 




Artesian wells. Suppose a a, to be a porous stratum lying upon 
an impervious bed of clays and marls, d; and covered by another 
mass of impenetrable rock e. Suppose now that at some point 
as at b, an opening be made which gives a free passage upward 
to the water confined at a a, at so low a level as to be subjected 
to the pressure of a considerable column of water, which we may 
suppose collected at f, in a more elevated district. The water 
will rush out at b, and rise to a considerable height; and if there 
should happen to be a natural fissure at c, a spring would be pro- 
duced. Among the curious facts made known by the borer, is 
the existence of distinct sheets of water, in strata of difreren 



! 






SPRINGS, 209 

ages and composition, and also of subterranean passages. At 
Tours, seeds and stems of marsh plants were brought up, and in 
such condition that they could not have been more than three or 
four months in water; and at Westphalia, small fish were thrown 
out, three or four inches long, the nearest streams being at the 
distance of some leagues. In boring an Artesian well near Buf- 
falo, recently, for the purpose of obtaining pure water for the use 
of the Gas Works, after having penetrated some 25 feet from 
the surface, the laborers came upon limestone rock ; upon pene- 
trating this rock twenty-five inches, the drill fell into a cavity, and 
upon being withdrawn a jet of water followed, and continued to 
flow, until the water in the well rose to the level of the lake. Sub- 
sequent observations have shown Lake Erie to be the supply 
fountain, for when the waters of the lake rise or fall, by the action 
of wind, the water in the well changes its level in conformity. 
It appears that one of the large and numerous fissures common 
in this particular series of rocks, and which in this case commu- 
nicated with the lake w T as pierced by the drill, and furnishes a 
fine illustration of the law which governs the production of 
springs and fountains. 

By the long continued action of underground streams, caverns 
and fissures, are formed and enlarged, and it is highly probable 
that rivers are flowing within the surface of the earth. In Staf- 
fordshire there is a spring which discharges annually more water 
than all that falls in the surrounding country. In Virginia, ten 
miles from Harrisburg, is a spring called the '• Big Spring." It 
rises suddenly from the foot of a limestone hill, and continues a 
stream some yards in breadth, and half a foot deep, with force 
sufficient to turn two large mills. At Kingston, Rhode Island, 
there is a spring which rises from primitive rocks, and dischar- 
ges such a quantity of water that ;. grist-mill has been driven by 
it for a great number or years, and more recently a large cotton 
factory has been erected, which depends entirely upon the water 
of this spring to turn the whole machinery. In flowing through 
the different strata, springs become impregnated with various min- 
eral substances. The solvent power of water exceeds that of 
any other liquid, and hence most spring waters are charged with 



210 THE WORLD. 

mineral substances; or with some gas. The presence of carbon- 
ate of lime, or lime in combination with carbonic acid, is easily 
shown by the calcareous lining or incrustation of a tea-kettle, or 
a boiler which has been sometime in use. Some springs contain 
so large a quantity of calcareous matter that they throw it down 
as they flow along, incrusting various objects which are placed in 
them. The springs of Derbyshire England, are particularly re- 
markable for this, and incrustations of leaves, branches, bas- 
kets &c, are easily procured. At the baths of San Fillippo, in 
Tuscany, where the waters are highly charged with carbonate and 
sulphate of lime ; medallions are formed by first directing the 
water to a cistern where the sulphate of lime, (gypsum) is de- 
posited. It is then conveyed to a chamber through a tube, from 
the end of which it falls ten or twelve feet, the current being bro- 
ken by numerous small sticks crossing each other, by which 
means the spray is dispersed about the room. - The moulds of the 
medallions are placed underneath, rubbed over with a little soap, 
and the water striking upon them leaves particles of carbonate 
of lime, which, gradually increasing, finally gives an exact and 
beautiful white crust-. So rapid is the deposition of earthy mat- 
ter by these springs, that a stratum of stone a foot thick is annu- 
ally deposited, and is employed for building purposes. The hill 
of San Vignorn, in Tuscany, a few miles from San Fillippo, has 
a thermal spring upon its summit, and from this opening, a deposit 
of travertine, or concretionary limestone has been formed two 
hundred feet thick, and of great hardness: We must be careful 
and not confound these incrustations with true petrefactions. In 
the one case, as for example an incrusted twig, the inclosed sub- 




stance will be found to have undergone no alteration, but that of 
natural decay, but a true petrefaction, is saturated throughout with 



CALCAREOUS SPRINGS. 211 

mineral matter, every part of its structure having undergone some 
change, so that if we break and polish such a specimen, every 
part of its structure, converted perhaps into flint, may be detected; 
even the minute ramifications and delicate tissues of many kinds 
of wood, and most delicate parts of the internal structure of bones. 
By the infiltration of water through limestone, rocks, the sparry 
concretions are made which depend in caves, like icicles, 
they are called stalactites, from a Greek word meaning to drop, 
and also under them, from the drippings, are stalagmites*, or drops, 
and when, as frequently happens, the two unite, a singularly pic~ 
turesque effect is produced, the caves appearing as if supported 
by pillars of extraordinary beauty and variety. Sometimes a 
iinear fissure in the roof, causes the formation of a translucent 
eurtain or partition. This is the case in Weyer's cave, in the 
limestone range of the Blue Mountains, a narrow and rugged 
fissure leads to a large cavern where the most grotesque figures 
present themselves, formed by the infiltration of water through 
the limestone. Passing from these the passage conducts to a 
flight of steps that leads into a large cavern of irregular form and 
great beauty, about thirty by forty feet in dimensions. Here the 
incrustations hang like a sheet of water that has been frozen as it 
fell. Farther on is another vaulted chamber, one hundred feet 
Song, thirty-six wide, and twenty-six high ; still farther is anoth- 
range of apartments, at the extremity of which, is a hall two hun^ 
dred and fifty feet long, having a splendid sheet of rock work 
running up the centre. The whole length of this extraordinary 
group of caverns is not less than one thousand six hundred 
feet. 

The most celebrated grotto in Europe, is in the island of Anti- 
paros, it consists of a series of caves, the roof, the floor, and the 
sides of which, are entirely covered with a dazzling incrustation. 
Immense columns of alabaster extend from the roof to the floor, 
and others hang in fine cubic forms above the head; the crystali- 
zation of alabaster has nowhere else been observed. 

Although the phenomena produced by incrusting springs, are 
perhaps not of much importance in modifying or changing the 
surface of the earth, yet the changes effected by this process, in 



212 



THE WORLB, 



strata composed of loose materials are of very great importance^ 
for by an infiltration of carbonate of lime, sand is converted into 
sandstone, and soft chalk into solid rock, and tho loose shells of 
Florida into compact stone. By this agency, the beds of recent 
limestone in which hnman skeletons are sometimes found, havo 
been formed, and are now in progress of formation, along tho 
shores of the whole West Indian Archipelago. On the norths 




oast corner of the main land of Guadalope is a bed of recent 
limestone, nearly submerged at high tides. In it are found shells,, 
fragments of pottery, stone arrow-heads, wooden and stone or- 
naments, and human skeletons. It is quite evident that the rock 
must have been soft and yielding when these remains were first 
deposited, they are not fossilized, for the bones still retain their 
gluten and phosphate of lime. In the wood cut, we give a repre- 
sentation of one of these human skeletons which is now in \he 
British Museum, it is that of a female ; the head of this skeleton 
has been carefully examined by*Dr. Moultrie, and is now in the 
museum of the Medical College at Charleston, South Carolina 



CALCAREOUS SPRINGS. 

This skeleton appears, from the craniological developments, to 
have belonged to a Peruvian, or to some one of a similar race, 
being entirely dissimilar to the skulls of the Caribs, or ancient 
possessors of the island. Another skeleton in a sitting posture is 
in the museum at Paris. The formation of this limestone is as 
follows. The sea which surrounds the Bermudas, abounds in 
corals, and shells, and from the* incessant action of the waves, 
the water becomes charged with calcareous matter, and a portion 
of this is borne by the waves to the shore, and deposited in the 
form of calcareous sand, which becomes compact limestone, on 
the infiltration of crystalized carbonate of lime. A great part of 
the detritus is thrown down in the depth of the ocean, and there 
envelopes the remains of vegetables and animals, forming new 
strata for the investigation of future ages. 

Carbonate of lime is not the only mineral substance held in so- 
lution by water, but silicious earth, or the basis of flint, which 
constitutes so large a proportion of the surface of the earth, is found 
in great abundance in some springs. It is true, that even in 
the present advanced state of chemical knowledge, we are unac- 
quainted with any process by which any large proportion of flint 
can be held in solution by water. Yet we have unquestionable 
proofs* that in the great laboratory of nature, this is effected on a 
large scale, as for example in the Geysers of Iceland, and the 
springs of Carlsbad in Bohemia, and the thermal springs of 
St. Michsel, in the Azores. It seems necessary in order that 
water should contain any large quantity of silica in solution, that 
it should be raised to a high temperature, and silicious springs are 
mostly thermal, and are generally found in volcanic regions. 
The most celebrated thermal springs are those of Iceland, termed 
the Geysers. The waters of these boiling springs contain a large 
amount of silex which is deposited on cooling, upon various sub- 
stances, similar to the incrustations of carbonate of lime already 
noticed. The hot springs of Iceland are situated in the south- 
west section of the island, and more than a hundred of them are 
found in a circuit of two miles. They rise through a thick cur- 
rent of lava, which may have flowed from Mt. Hecla, whose sum- 
mit may be seen at a distance of about thirty miles. It is said 



214 



THE WORLD. 



that the rushing of the waters may be heard as they flow in their 
subterranean channels. The springs are intermittent, a fountain 
of boiling water accompanied with a great evolution of vapor, 
first appears, and is ejected to a considerable height, sometimes 
as much as one hundred feet, a volume of steam succeeds, and 
is thrown up with great force and a loud noise, similar to the es- 
cape of steam from the boiler of%n engine. This operation con- 
tinues sometimes for more than an hour, though generally not 
longer than ten minutes, and is succeeded by a period of rest of 
uncertain duration, and then a repetition of the same phenomena. 
We give a view of the crater of the great Geyser reduced by Mr. 
Lyell, from a sketch by J. W. Hooker, M. D. The basin of the 
great Geyser is an irregular oval about fifty-six feet, by forty-six, 
the silicious mound of which it is formed, is about seven feet 
high. In the centre is a pipe seventy-eight feet in perpendicular 
depth, and about sixteen feet diameter at the top, but contracting 
to ten feet lower down. The circular basin is represented as 




empty, but it is usually filled with a beautifully transparent water 
in a state of ebullition ; the inside of the basin is smooth and 
formed of a whitish silicious deposit, as are also two channels at 



SILICIOUS SPRINGS. 215 

each side, by which the water escapes when the basin is full. It 
is said that an eruption may be brought on in a few minutes by 
throwing stones down the pipe, these are again ejected, oftentimes 
with immense violence. The theory of the action of these hot 
springs of Iceland has not yet been satisfactorily given ; the heat 
however, is supposed to be derived from subterranean volcanic 
fires. The silicious water from these springs incrusts plants, 
twigs, and leaves, similar to the calcareous springs. In the island 
of St. Michael there are hot springs very strongly impregnated 
with silica; wherever the water has flowed, sinter or precipitated 
rock, is formed intermixed with the clay, including grass, ferns, 
and reeds, in different stages of petrefaction ; branches of the 
same ferns which now flourish in the island are found completely 
petrified, preserving the same appearance as when vegetating. 
There are many springs in this country which deposit silicious 
and calcareous matter. 

Iron is found in the waters of almost all springs, and some of 
them are so copiously impregnated with this metal that they stain 
the rocks or herbage over which they flow. The iron which is 
thus borne out of the earth and deposited into the sea, acts as a 
cement to bind together the subaqueous deposits now forming 




-Many of the ancient sandstones are cemented and colored by 
iron, and pebbles are firmly bound together in ferruginous con- 



216 THE WORLIh 

glomerate. Occasionally nails, or other pieces of iron, are found 
in the centre of a hard nodule of sandstone, formed by this pro- 
cess. The engraving, from Dr. MantelFs M Wonders of Geolo- 
gy," is a very interesting specimen, it is a conglomerate of glass 
beads, knives, and sand, cemented together by an infiltration of 
iron, derived from the oxidation of the blades. It contains two 
silver pennies of Edward I, and was dug up at a depth of ten 
feet in the river Dove in Derbyshire. The coins are presumed 
to have been a part of the treasures contained in the military chest 
of the Earl of Lancaster, which was lost in crossing the river in 
the dark ; more than five centuries must therefore have elapsed 
since its submersion. The ore called bog-iron, is formed by the 
infiltration of water impregnated with iron, and various kinds of 
wood are colored black by the same cause. Iron, it is well known 
is one of the chief ingredients in many celebrated mineral wa- 
ters, frequently in the shape of a carbonate. The consolidation 
of sand and other loose materials by the agency of mineral wa- 
ters, is everywhere going on, and in much greater extent than 
can be easily comprehended ; small and apparently simple as are 
the means employed, yet the effects are magnificent. 

The detritus borne down by the mountain streams falls at last, 
quietly into the ocean, or is deposited upon the rich soil of some 
delta, after a certain time the mass is cemented together by other 
mineral ingredients dissolved in the water, and beds of compact 
stone, in which are entombed the remains of animate and inani- 
mate existence, are formed slowly but surely, for the use of most 
distant generations. The twigs and leaves, and insects, which 
fall into the petrifying springs are incrusted with a coating of 
stone, or are slowly transmuted into mineral substance for the 
inspection and admiration of a future race. Thus the change 
continually goes on. The frost, the storm, and the stream, and 
in many volcanic districts the carbonic acid, continually given off, 
as for example, in the neighborhood of the extinct volcanoes of 
Auvergne in France, cause even the granite rocks to crumble 
and fall away; but in a thousand other places the process of re- 
union is going on, and different kinds of stone are being formed 
from the ruins of the old. Besides the springs to which we have 



5ALT SFRLNGS. 2l"?~ 

referred, there are others very numerous impregnated with petro- 
leum, and the minerals allied to it, as bitumen, naptha, asphaltum 
uid pitch. These springs are found in all parts of the globe, but 
the most powerful yet known, are those on the river Irawadi, in 
the Birman Empire, there being five hundred and twenty wells 
in one locality, yielding annually 400,000 hogsheads of petroleum. 
On both sides of the island of Trinidad, fluid bitumen is seen to 
ooze up from the sea. In the island is a pitch lake about three 
miles in circumference. The asphaltum is sufficiently hard to 
support heavy weights in cold and wet weather, but during warm 
weather it is nearly fluid. In some places it is covered by the 
soil, and large crops of tropical productions are raised upon it, so 
that it is difficult to ascertain the boundaries of the lake. Mr. 
Lyell supposes that the materials for the formation of this bitu- 
men, have been borne down by the Oronoco into the sea; and, col- 
lected by eddies or other causes into particular regions, have been 
acted upon by submarine volcanic fires. The frequent occur- 
rence of earthquakes, and other volcanic phenomena in the island, 
lends countenance to this opinion. 

In addition to those above mentioned, we may enumerate 
the saliferous or brine springs, which are everywhere so common 
over the globe. The agency of these springs, in the formation 
of rocks, is of less importance than that of the calcareous, or the 
silicious. Often they are strong solutions of pure rock salt, or 
muriate of soda, and furnish large quantities of that valuable ar- 
ticle for the purposes of domestic economy. Such are the salt 
springs in the neighborhood of Salina, and Syracuse, in the State 
of New York. At Salina, the well is seventy feet deep, and 
about 4S0 gallons of brine are raised in one minute, and Dr, 
Beck states that 43J gallons are required to yield a bushel of salt, 
weighing 56 lbs. The well at Syracuse 170 feet deep, the pumps 
raise 62 gallons per minute, and 46 gallons are required to make 
a bushel of salt. The water is clear and sparkling, and of a tem- 
perature of 50° (Fahr.) at Salina, and 51° at Syracuse. These 
salt springs are supposed to be owing to immense beds of rock 
salt, although no borings yet made, have reached these beds. The 
valleys of the Mississippi and the Ohio abound in salt springs, 



218 THE WORLD. 

and are based almost wholly on the saliferous or salt bearing rocks. 
Two distinct strata of these salt rocks, known as the upper and 
lower salt rocks, are found on the Muskingum, about 400 feet 
apart. The stone itself is a white, or sometimes reddish tinted and 
porous sandstone, the upper, is 25 feet thick; and the lower 40, and 
this yields the strongest brine. At Cheshire England, are nu- 
merous brine springs, and the salt springs of Droitwitch, a small 
town in Worcestershire, are superior to any other in the island; 
they are supplied from beds of rock salt, or rather veins, lying be- 
low a bed of gypsum ; for a long time the salt was made only 
from the brine which penetrated this bed, but about a century ago 
it was bored through and a large salt river was found to flow be- 
low. The depth of the river of brine below the surface, is about 
200 feet, 150 of which are gypsum ; the river flows over a bed of 
rock salt and is twenty-two inches deep. The origin of these 
extended deposits of salt has not yet been satisfactorily ascertained. 
The waters of the Dead Sea in Palestine, contain large quantities 
of muriatic salts, derived from entire rocks of this mineral, con- 
tinually dissolving on its southern shore. The water contains 
forty-one parts in one-hundred of salt ; a much greater propor- 
tion than that of the sea. It is impregnated also with other min- 
eral substances, particularly bitumen, which floats upon its sur- 
face in such large quantities as would elsewhere sink. The vol- 
canic appearance of the country, the almost perpendicular, black 
rock which bounds its eastern or Arabian side, and throws its 
olack shadow over the dark waters, and the limestone and sandy 
cliffs on its western side, which tower up in fanciful shapes, lends 
countenance to the opinion that these mineral substances are the 
products of former volcanic action. We have now glanced at the 
most prominent effects of springs in modifying and changing 
the face of the globe ; although the effect of any individual spring 
appears trifling, yet the aggregate of change either by disintegra- 
ting, or consolidating, is immense. We have already alluded to 
the transporting power of rivers. The small stream which is 
supplied by springs, and which flows for hundreds of miles with 
a power which seems scarcely sufficient to carry along a fevy 
sands, by continual accessions swells finally into an immense 



SUBTERRANEAN SPRINGS* 219 

river, and when, from long continued rains, or from melting of 
snows and ice, the brooks and tributary streams are swollen, a 
flood of water is poured down to the ocean, which bears with it 
materials transported a thousand miles, and in quantities of which 
we can form little conception. The water, which falls upon the 
surface of the earth and penetrates its upper soil, and is thus pro- 
tected from evaporation, descends lower and lower, until it meets 
some impervious bed of clay, or marl ; here it accumulates and 
forms a hidden pond, and slowly undermines whole tracts of 
country, and in the course of ages subterranean rivers are formed. 
The various mineral ingredients dissolved in water, are borne 
up by springs, and again flowing over or through the porous sands, 
form limestones, sandstones, and ironstones; and thus continu- 
ally the process is going on. 

The action of all springs, and running waters, is to level the 
surface of the earth. The streams, which always flow from an 
elevated source, bear down the disintegrated portions of moun- 
tains and hills, and tend continually to fill up the bed of the sea. 
Unless a counterbalancing cause existed, and the elevation was 
made to compensate this continual degradation or levelling, the 
whole dry land would ultimately disappear. We find in earth- 
quakes and other volcanic eftects the elevating power; and al- 
though, as \^e shall presently show, the sea may gradually en- 
croach upon the shores of one country, yet the lands of another 
will be gradually upheaved, and something like a balance will be 
maintained. Minute therefore as are the transmutations which 
are going on continually around us, and by which, long since, in 
the same quiet manner, the leaf that floated down the stream, a 
thousand years ago, and the insect that dropped into water, have 
been incrusted, and preserved with a fidelity which mocks the 
sculptor's art, yet we see that processes like these, have 

M Turned the ocean -bed to rock, 
And changed its myriad living swarms 
To the marble's veined form^. ? ' 

" How marvellous" observes Sir Humphry Davy, "are those 
laws by which even (he ' 'imblest types of organic existence are 



; 



220 THE WORLD. 

preserved, though born amidst the sources of their destruction; 
and by which a species of immortality is given to generations, 
floating, as it were, like evanescent bubbles on a stream raised 
from the deepest caverns of the earth, and instantly losing what 
may be called its spirit in the atmosphere." 



AQfEOUS CAUSES OF CHANGE. 223 



CHAPTER V. 

Currents. 

M Thy shores are empires, changed in all save thee — - 
Assyria, Greece, Rome, Carthage, what are they I 
Thy waters wasted them while they were free, 
And many a tyrant since : their shores obey 
The stranger, slave, or savage ; their decay 
Has dried up realms to deserts : — not so thou, 
Unchangeable, save to thy wild wave's play — 
Time writes no wrinkle on thine azure brow — 
Such as Creation's dawn beheld, thou rollestnow V 9 

Byron. 

We are now to consider the remaining* aqueous causes of 
change, currents and tides. The joint action of these produce 
mutations of great geological interest. The tides, or the great 
tidal waves which flow over the surface of the ocean at stated in- 
tervals, are mainly caused by the attraction of the moon, and 
hence we may show, and by no very extended chain of causation,, 
that the effect of the moon in altering and keeping in a state joi 
perpetual mutation the face of the earth, is by no means incon- 
siderable. A more remote cause, the rotation of the earth upon 
its axis, produces in part at least, great currents which constantly 
flow in vast circuits in the Atlantic, Pacific, and Indian oceans. 
In addition to the circular currents which thus flow through the 
oceans which we have named, there are immense bodies of cold 
water continually moving from the polar regions towards the 
central portions of the earth, and, as these currents are exhibited 
superficially, or on the surface, bearing down immense fields of 
ice, and since the storms and fogs of those regions are not suffi- 
cient to supply this waste of the waters, we may infer that an un- 
der current of warmer water passes continually from the equa- 
torial to the polar regions. The polar current of the southern re- 
gions seems to be more powerful than that of the northern. Ice 



222 THE WORLD. 

islands from 250 to 300 feet above the level of the sea, have been 
occasionally seen off the Cape of Good Hope, and were there- 
fore of immense bulk, as for every solid foot seen above, there 
must have been at least eight cubic feet below water. The wood 
cut below exhibits one of these ice-islands, sketched by Capt. 
Horsburgh; it was seen off the Cape of Good Hope, in April 
1829; it was two miles in circumference and about 150 feet high, 
appearing like chalk when the sun was obscured, and having the 
lustre of refined sugar when the sun was shining upon it. 




Undoubtedly the principal causes of Oceanic currents are the 
trade -winds, of which we have already spoken. These blowing 
at first directly from the north and south, over the surface of the 
water, move the floating ice, and superficial water, in the same 
general direction, thus at length generating a strong polar current. 
The south polar current being less intercepted by the peculiar 
formation of the antarctic lands, than the northern, is perceptible 
in much higher southern latitudes than the current from the 
north. A manifest influence is thus exerted upon the climate, to 
which we shall again allude. 

The rotation of the earth, when the waters have been set in 
motion from the north to the south, causes a great change in the 
general direction of these currents precisely upon the same princi- 
ple which has long been recognized in the case of trade winds. 
For example, the current which flows north from the Cape of Good 
Hope towards the Gulf of Guinea, has a rotary velocity when it 
doubles the Cape of about 800 miles per hour, but when it reaches 
the equator, the surface of the earth is there whirled around at 



GULF STREAM. 223 

the rate of 1000 miles an hour, or 200 miles faster. Now if the 
water was to be suddenly transferred from the Cape to the equa- 
tor, this deficiency of motion would cause, (inasmuch as the earth 
rotates from west to east) a very strong current flowing westward 
at the rate of 200 miles an hour ; or with sufficient power to sub- 
merge the western continent. No disturbance however occurs, 
for the water, as it advances into new zones of sea which are mov- 
ing more rapidly, gradually acquires the different velocity by fric- 
tion, so that a gentle easterly, or south-easterly current is the re- 
sult. When the water flows from equatorial to polar regions, a 
contrary current is produced ; thus the Gulf Stream, issues from 
the Bahama Channel with a rotary velocity of 940 miles an 
hour, but when it reaches latitude 40°, the water is there moving 
with a rotary velocity of 766 miles an hour, or 174 miles an hour 
slower, hence a westerly or south-westerly current is the result 
from the excess of rotary motion retained by the stream. • 

Having shown some of the causes that produce oceanic cur- 
rents, we will now consider more in detail the most important. 
From the best accounts which we have been able to obtain, there 
seems to be a general set of the waters westward from the west- 
ern coast of Peru. This current flows nearly westward, but is 
not much perceived until its entrance into the Indian Ocean, when, 
strengthened by the northerly currents flowing from the 2yyth 
Pacific, it flows along the east coast of of Africa ; after passing 
through the Mozambique Channel, between Madagascar and the 
continent, it unites with another current from the Indian Ocean, 
and is deflected by the Lagullas banks, which lie off the southern 
point of Africa, around the Cape of Good Hope. The collective 
stream is about one hundred and thirty miles in breadth and from 
7° to 8° warmer than the neighboring water, and runs from the 
rate of two and a half to more than four miles an hour. The 
Lagullus bank rises from an immense depth to within one hun- 
dred fathoms of the surface, and has perhaps been formed by the 
joint action of a south-eastern and north-eastern current, which 
meet here. As the main'body of the current does not flow over 
this bank we may conclude its total depth to be much more than 
one hundred fathoms. We give here a little chart showing the 



224 



THE WORLD. 



general direction of the great oceanic currents. The Lagullus 
current after doubling the Cape of Good Hope, passes northward 




along the western shores of Africa, and is called the South At- 
lantic current. It then enters the Bight, or Bay of Benin, and is 
deflected westward, partly from the form of the coast and partly 
by^he action of the Guinea current flowing from the north into 
the same great bay. From the centre of this bay it proceeds in 
an equatorial direction westerly, at the rate of ten or eleven miles 
a day, to the coast of Brazil where it is divided, a portion flowing 
feebly southward ; the other branch passes off the the shores of 
Guinea by the West India islands, towards the Musqueto and 
Honduras coasts, through the Carribean sea, flowing northwards, 
passes into the Gulf of Mexico, following the bendings of the 
shore from Vera Cruz to the mouth of the Rio del Norte, thence 
to the mouths of the Mississippi where it receives a new impulse; 
after performing this circuit, it rushes with great impetuosity 
through the Bahama Channel, its velocity being about five miles 
an hour, and breadth from thirty-five to fifty miles. Its course 
is now north-easterly along the eastern coast of North America, 
its breadth increasing and its velocity diminishing. As the cur- 



Oceanic currents. 225 

rent moves along northward, it retains a large proportion of the 
warmth which it had in the Gulf, and is easily recognized from 
the rest of the ocean by its higher temperature, even as far north 
as the banks of Newfoundland, where the temperature is from 
8° to 10° above the surrounding ocean. To the east of Boston 
and in the meridian of Halifax, the stream is two hundred and 
seventy-six miles broad. Here it is suddenly turned to the east, 
its western margin touching the extremity of the great bank of 
Newfoundland, where the current sends off a branch which pro- 
ceeds to the north-east, sometimes depositing tropical fruits and 
seeds upon the coast of Norway, and the shores of Ireland and 
the Hebrides. The main current continues to flow and spread 
out until, in the neighborhood of the Azores, it is about five hun- 
dred miles in breadth. From the Azores it flows towards the 
straits of Gibraltar, the island of Madeira, and the Canary isles, 
along the western shores of Africa as far south as Cape Verd, 
where it is again deflected by meeting the great equatorial cur* 
rent flowing from the coast of Guinea to the Brazils. In this 
manner, according to Humboldt, the waters of the Atlantic are 
carried around in a continual whirlpool, performing a circuit of 
13,000 miles in about two years and ten months. The branch of 
the Gulf Stream which is given off near the banks of Newfound- 
land, passes northward and eastward by the coast of Scotland and 
Norway, as far as the North Cape, where, being met by a polar 
current from Nova Zembla, it is deflected westward along both 
sides of Spitzbergen ; still influenced by the polar current, it 
passes along the shores of Greenland to Davis* Straits, where it 
meets a fourth current from Baffins Bay, which deflects it south- 
ward towards the banks of Newfoundland, where it again meets 
the Gulf Stream. Thus two great whirlpools, connected with 
each other and revolving in opposite directions, touch at the 
Banks of Newfoundland, which seems to be a bar cast up by 
their conflicting waters. Branches of the Gulf Stream sent off 
at the Azores, set from the Bay of Biscay through the English 
Channel, and through St. George's Channel. The general di- 
rection of these great currents may be observed on the little chart 
preceding. Besides these great currents, there are local or tern* 



S26 THE WOtlLl). 

porary currents, produced by winds, the discharge of rivers, the 
melting of ice, &c* 

The great oceanic currents however depend upon no tempor* 
ary or accidental circumstances, but like the tides, on the laws 
which regulate the motions of the heavenly bodies. The lines 
of coast which are subjected to their continual action, are under- 
going perpetual change, the amount of this change being depen- 
dant upon the exposure, and the actual constitution of the coast. 
We find everywhere, the most lofty cliffs, promontories, and pre- 
cipices, whatever be their composition, whether like the primary 
deposits of the Shetland isles, or like the chalk cliffs of Dover, or 
the diluvium of Boston Harbor, all in a state of rapid and fear- 
ful destruction, crumbling away more or less quickly according to 
the hardness and crystalline character of the materials which 
compose them. The whole of Boston Harbor, which is now dot- 
ted with small islands, was once one piece of solid land. The 
diluvium which formerly covered the rocks, has been gradually 
worn away by the ocean, the outermost islands present nothing 
but the bare rock, and the inner ones are now being denuded. 
Indeed, as Prof. Hitchcock observes, when writing of the effect 
of the ocean upon coasts exposed to its fury, " It is difficult to 
examine the coast of Nova Scotia and New England, to witness 
the great amount of naked battered rocks, and to see harbors and 
indentations, chiefly where the rocks are rather soft, while the 
capes and islands are chiefly of the hardest varieties, without 
being convinced that most of the harbors and bays, have been 
produced by this agency." To witness in perfection the immense 
power of the waves, urged by the tempests and currents upon 
the coasts exposed to their irresistable force, we must visjt the 
northern isles of Scotland, and behold steep cliffs hollowed out 
into deep caves and lofty arches; and immense blocks of stone 
overturned and carried incredible distances. In the winter of 
1802, in the isle of Stenness, says Dr. Hibbert, a tabular shaped 
mass of rock, eight feet two inches, by seven feet, and five feet 
one inch thick, was dislodged from its bed and removed to a dis- 
tance of from eighty to ninety feet ; and on Meikle Roe, one of 
the Shetland isles, a mass of rock twelve feet square, and five 



fcJtCftOACHMJUiTS OF IH£ S.LA. 



2* 



feet in thickness, was removed from its bed fifty years ago, to a 
distance of thirty feet, and has since been twice turned over. 

The long continued and violent action of the surf, finally frets 
away the softer parts of islands, and nothing remains but fanci- 
ful clusters of rocks, and mere shreds and patches of masses once 
continents. We give below a view of the cluster of rocks to the 
south of Hillswick Ness, one of the Hebrides, from a sketch by 




Dr. Hibbert. These fantastic shaped rocks, which are all that re- 
main of what was once an island covered with vegetation, are 
striking monuments of that incessant change which, continually, 
though silently and almost unnoticed, is going on, but whose 
final effects are of the most magnificent character. Examples of 
such rocks as are figured above, are found in many places along 
the coast of the United States, where it is exposed to the action 
of the storms of the Atlantic. We may be able to form some 
idea of the degrading power of the ocean from the following 
statement, which is given on the authority of Lieut. Mather, ge- 
ologist to the first district of the state of New York. 

M Vast masses of the cliffs of loam, sand, gravel, and loose 
rocks, of which Long Island is composed, are undermined and 
washed away by every storm. The water on the ocean coast, to 
some distance from the shore, is almost always found to have 



228 THE WOULD. 

more or less earthy matter in suspension, much of which, except 
during storms, is derived from the grinding up of the pebbles, 
gravel, and sand, by the action of the surf. This earthy matter 
is carried off during the flood tide, and in part deposited in the 
marshes and bays, and the remainder is transported seaward dur- 
ing the ebb, and deposited in still water* After a close observa- 
tion, I have estimated that at least 1000 tons of matter is thus 
transported daily from the coast of Long Island, and probably 
that quantity, on an average, is daily removed from the south 
<coast, between Montauk Point and Nepeaque Beach. This shore 
of 15 miles in length, probably averages 60 feet in height, and is 
rapidly washing away ; 1000 tons of this earth would be equal to 
about one square rod of ground, with a depth of 60 feet. Allow- 
ing this estimate to be within proper limits, more than two acres 
would be removed annually from this portion of the coast. It is 
probable that any attentive observer would not estimate the loss 
of land there at less than this amount. Nearly one half the mat- 
ter coming from the degradation of the land is supposed to be 
swept coastwise in a westerly direction. There are many evi- 
dences that the east end of Long Island was once much larger 
than at present; and it is thought probable that it might have been 
connected with Block Island, which lies in the direction of the 
prolongation of Long Island." 

A remarkable exhibition of the conjoint power of waves and 
currents was exhibited during the building of the Bell Rock 
Lighthouse. The Bell Rock, on which it stands, is red sand-* 
stone, about twelve miles from the mainland, and from twelve to 
sixteen feet under the surface at high water. At a distance of 
100 yards from the rock, there is a depth in all directions, of two 
or three fathoms at low water. During the erection of the light- 
house in 1807, six large blocks of granite, which had been land- 
ed on the reef, were carried away by the force of the sea, and 
thrown over a rising ledge to the distance of twelve or fifteen 
paces, and an anchor weighing 22 cwt. was thrown up upon 
the rock. We are informed by Mr. Stevenson, that drift stones 
of more than two tons weight, have, during storms been often 
thrown upon this rook from the deep water. 



ENCRGACHMENTS OF THE SEA* 229 

The eastern coast of England has been greatly changed by the 
action of the waves, the ancient sites of towns and villages, being 
now sand banks in the sea. The whole coast of Yorkshire, from 
the mouth of the Tees to that of the Humber, is in a state of 
comparatively rapid decay ; the inroads of the sea at different 
points being limited by the nature of the soil, or the hardness of 
the rocks. Pennant, after speaking of the silting up, or filling 
up with water transported sand, clay, gravel, &c, of some an- 
cient posts in the estuary of the Humber, observes, " But in re- 
turn, the sea has made most ample reprisals, the site, and even 
the very names of several places, once towns of note on the 
Humber, are now only recorded in history; Havensper was at 
onetime a rival to Hull, and a post so very considerable in 1332, 
that Edward Baliol, and the confederated English barons, sailed 
from hence to invade Scotland ; and Henry IV. in 1399, made 
choice of this port to land at, to effect the deposal of Richard II; 
yet the whole of this has long since been devoured by the merci- 
less ocean ; extensive sands, dry at low water, are to be seen in 
its stead." Instances like these are not rare, the towns of Cro- 
mer, and Dunwich, are both lost, swallowed up by the ocean, 
which is now encroaching at Owthone at the rate of about four 
yards a year. At Sherringham, in Norfolkshire, where the pres- 
ent inn was built in 1805, and the sea was a distance of fifty yards, 
the mean loss of land being about one yard annually, it was cal- 
culated that it would require about seventy years before the sea 
would reach that spot, but between the years 1824 and 1829 no 
less than seventeen yards were swept away, and a small garden 
only, was left between the house and the sea, and when Mr. 
Lyell in 1829 visited the place, he found a depth of twenty feet, 
(sufficient to float a frigate), where, only forty-eight years agO', 
stood a cliff fifty feet high. Mr. Lyell justly remarks, " If once 
in half a century an equal amount of change were produced sud- 
denly, by the momentary shock of an earthquake, history would 
be filled with records of such wonderful revolutions of the earth's 
" surface; but if the conversion of high land into deep sea be grad- 
ual it excites only local attention." The flag-staff of the Preven- 
tive Service station, on the south side of the harbor, has, within 

K 



2'dQ 



THE >VG'Kf.{7, 



the last fifteen years, been ihrice removed inland, in consequents 
of the advance of the sea. 

Along the whole eastern coast of England, changes similar to 
these are going on. In some places by the silting up of estuaries, 
land is forming, but not near as much, as is being removed. The 
isle of Sheppey, which is a tertiary formation, now about six 
miles long, by four in breadth, is rapidly decaying on its north 
side, fifty acres of land having been lost within the last twenty 
years. To the east of Sheppey stands the Church of Reculver, 
upon a clifi* of clay and sand, about twenty-five feet high. This 
place was formerly an important military station in the time of 
the Romans, and even so late as the reign of Henry VIII, was 
nearly one mile distant from the sea. 




We here give a view of the Church of Reculver taken in the 
year 1781, copied from the Gentleman's Magazine. At this time 
the spot had become interesting from the encroachment of the 
water. It represents considerable space as intervening between 
the churchyard and the cliff. In the year 1782, the cottage at ( 
the right was demolished ; nearer the church is shown an ancient 
chapel now destroyed, and at the extreme right is the Isle of 
Sheppey. In the year 1806, a part of the Churchyard with some 



ItECULVEIl CHURCH. 



231 



oi tlie adjoining houses was washed away, and the ancient 
church with its two lofty spires, a well known land-marfc, was 
abandoned. The following view of it as it -appeared in 1834, is 
taken from Mr. Lyell's Principles of Geology, from which the 
preceding statement is also derived. This ancient building would 




probably, have fallen long since, had not the force of the waters 
been checked by an artificial causeway of stones, and large wood- 
en piles, driven into the sands to break the force of the waves. 

There are good reasons for believing that the coasts of France 
and England were formerly united, this is inferred from the iden- 
tity of the composition of the cliffs on the opposite sides of the 
channel, and also of the noxious animals in England and France, 
which could hardly have been introduced by man. This opinion is 
advocated by many distinguished geologists, and it is by no means 
incredible, that in the course of ages the sea may have forced its 
passage through. The separation of Friesland, which was once 
a part of North Holland, from the mainland, by the action of the 



232 rHE WORLD. 

sea in the thirteenth century, and the formation of a strait of 
about half the width of the English channel in 100 years, lends 
countenance to this opinion. The inroads of the sea have no 
where been more severe than in Holland, and even at the pres- 
ent day 12,000 windmills are employed to drain the Netherlands 
and to prevent at least two-thirds of the kingdom from returning 
to the state of bog and morass, and during the past year three 
immense steam engines, capable of discharging 2,800,000 tons 
of water in 24 hours, have been employed in pumping out and 
emptying through the great ship canal, and sea-sluices at Katwyk, 
the lake of Haarlem, which by its continual inroads threatened to 
inundate Amsterdam on the one side, and Leyden on the other. 
In the year 1836, twenty-nine thousand acres of land were com- 
pletely overflowed by it. The large lake called the Bies Bach 
was formed in 1621, by the sea bursting- through the embank- 
ments of the river Meuse, overflowing seventy-two villages. Of 
these villages no vestiges of thirty-five of them were ever dis- 
covered. Since their destruction an alluvial deposit has been 
formed partly over their site. The island of Northstrand, which 
in the year 1634, contained 9000 inhabitants, and was celebra* 
ted for its high state of cultivation, was, on the evening of the 
11th of October, in that year, swept away by a flood which de- 
stroyed 1300 houses, 50,000 head of cattle, and 6000 men, leav- 
ing three small islets, one of them still called Northstrand, which 
are continually being wasted away by the sen. Such are some of 
the powerful effects of currents and waves in altering, and finally 
sweeping away the headlands and islands which at any particular 
epoch may have distinguished the line of coast exposed to their 
force ; the eastern side of America, along the Atlantic coast is 
subject to the same changes. Before leaving this part of our 
subject, we will describe that peculiar tidal wave called "the 
Bore." This is produced, when the channel of a river, into 
which the tidal wave from the ocean is entering, is so narrow that 
the water is made to rise suddenly, and thus terminates abruptly 
on the side away from the sea, or inland ; precisely like the waves 
which break upon a shelving shore. As might be expected, this 
phenomenon occurs most powerfully at the time of spring, or high- 



THE BORE. 233 

est tides. The Bore which enters the river Severn is sometimes 
nine feet high, and at spring tides rushes up the estuary with ex- 
traordinary rapidity. In the Hoogly or Calcutta river, says Ren- 
nell, M the Bore commences at Hoogly point, the place where the 
river first contracts itself, and is perceptible above Hoogly town; 
and so quick is its motion, that it hardly employs four hours in 
traveling from one to the other, though the distance is nearly 
seventy miles. The tides of the Bay of Fundy pour twice*a day 
vast bodies of water through a narrow strait, causing in every 
small stream, an immense tidal wave, rising sometimes to the 
height of seventy feet. We have already alluded to its rich 
alluvial deposits of red marl which have been excluded artificially 
from the sea by embankments. 

Heretofore we have noticed only the degrading effects of cur- 
rents, and tides. It might at first appear that the sediment borne 
down by rivers, the formation of deltas, and the silting up of 
estuaries, would compensate for the loss by the encroachments of 
the sea, this however, is not the case; while in all instances the 
new-made land is constantly attracting attention, there are no 
boundaries, or great natural land marks, to show where was 
formerly the line of coast. The former demand attention by 
their presence, the latter are unseen, and therefore lightly esti- 
mated; many places where once flourishing cities stood, are now, 
not only depopulated, but covered with water to a depth of thirty 
feet. There is therefore good reason for believing that the loss 
of land by the effects of currents and tides, much more than 
counterbalances all deposited in the form of dry land. 

The general tendency of these encroachments is undoubtedly 
to fill up the bed of the sea, and to finally reduce the surface of 
the earth to a uniform level ; and this would ultimately be ac- 
complished, but for the counterbalancing force of volcanic or ig- 
neous causes, which are continually elevating the surface. If 
we had space we might continue to enumerate examples of the 
effects of the ocean in destroying the coasts, not only of our own 
country, but over the whole world : sufficient however has been 
said to give some idea of the importance of these causes of change, 
and when hereafter, we allude to immense formations of rock 



234 THE WORLD. 

strata, imbedding numerous fossils, as the sedimentary deposit of 
an ancient ocean, the statement will not appear incredible. The 
force of the current of the Amazon extends out into the ocean to 
a distance of three hundred miles from its mouth, and when we 
remember how long the mud and fine sand remains suspended 
even in quiet water, we shall not be surprised to learn that parti- 
cles brought down from the interior of South America, are per- 
haps deposited in the Mexican Gulf; for where the great equato- 
rial current from the coast of Guinea crosses the waters of the 
Amazon, it runs with a velocity of four miles an hour. Vast 
quantities of drift wood and rubbish are thus carried as far as the 
mouths of the Orinoco, and are increasing the island of Trini- 
dad. It is the opinion of many distinguished philosophers that 
the Isthmus of Suez, which now separates the Mediterranean 
and the Red Sea, is a recent formation, it is at least quite certain 
that the isthmus is receiving continual accessions on ihe Medi- 
terranean side. The change of coast, the loss of cities, the for- 
mation of bays, the filling up of estuaries and washing away of 
islands, important as these changes may be, are nevertheless, of 
less moment than the processes going on in the depths of the 
sea ; far below, where the waters are never disturbed by the 
storms and winds, which lash the surface into fury, a quiet de- 
posit is going on, in this are now being imbedded the various 
forms of animal existence which are borne down to the bottom of 
the ocean. Nor are these all, the wealth of man has gone down, 
and lies hurried deep with his bones in the undisturbed strata. 
At some distant epoch, when the present ocean bed shall be up- 
heaved, perhaps some patient investigator will exhume the fossils, 
and moralize upon the eventful change which passeth over all 
things. We cannot close this chapter better than with the beau- 
tiful language of Mrs. Hemans : 

" The depths have more ! What wealth untold 

Far down and shining through their stillness lies ! 
They have the starry gems, the burning gold, 
Won from a thousand royal argosies ! 

Yet more — the depths have more ! Their waves have roll'd 

Above the cities of a world gone by — 
Sand hath filled up the palaces of old, 

Sea-weed o'ergrown the halls of revelry." 



WTNKOUS CA<T KS U*' CHANGE. '235 



CHAPTER V i . 

Volcanic Chains* 

" Yon dreary plain, forlorn and wild, 
The seat of desolation, void of light, 
Save what the glimmering of these flames 
Casts pale a id dreadful." Milton. 

We have in the preceding chapters given somewhat in detail 
an account of the various aqueous causes of change, now in ope- 
ration. We shr il consider in the present chapter the igneous 
causes of change, or volcanic action ; and in order to economise 
the little space v e can allow, will consider them as follows. First, 
we shall give a sketch of the geographical distribution of the 
chief volcanoes now active, or which have been active within the 
historic era. We shall next give an account of the principal 
earthquakes, aid other volanic phenomena which have disturbed 
the earth's surface; and lastly, consider such changes, supposed 
to be due to internal igneous agency, as the gradual elevation and 
depression of various tracts of country. It would be out of place 
for us to discuss at present, the question, whether the interior of 
the globe is in a state of fusion, and that the eruptive force of 
volcanoes is the occasional liberation of the molten mass, acted 
upon by the intense pressure of the superincumbent strata, or by 
confined gases and vapors ; or whether the intense heat wjiich 
melts masses of rock, causing the most violent convulsions, is 
caused by chemical action, i. e. the union of oxygen derived 
from water or the air, with the metallic bases of the earths and 
alkalies, forming silica, alumina, lime, soda, &c, substances 
which predominate in lavas; or whether it be a union of both 
hese causes. In our own opinion it is neither, but is the result 



236 THE WORLD. 

of simple mechanical action, produced in a manner we cannot 
here describe. 

Volcanoes are found distributed all over the surface of the earth v 
though more prevalent in some portions than in others. Many 
of the islands in the Pacific and Atlantic are of volcanic origin; 
perhaps the majority of them. In some parts of the earth vol- 
canoes stand alone, but they are mostly connected with extensive 
mountain ranges, extending in a linear direction, and we may 
select three distinct regions of subterranean disturbance. The 
most extensive is that of the Andes. Along the whole western 
shores of North and South America, extends a lofty mountain 
chain, remarkable not only for its position, but also for its 
collosal form, the nature of the masses of which it is com- 
posed, and of the materials ejected. Along the whole extent of 
this chain, volcanoes occur, and between, the 46th deg. of south 
latitude to the 27th deg. is a line of volcanoes so uninterrupted 
that scarcely a degree is passed without the occurrence of one of 
these in an active state ; about twenty now active are enumera- 
ted in this space, and doubtless there are very many more which 
have been active at a recent period. When we remember how 
long a time Vesuvius had remained quiet, before it again renewed 
its activity, and overwhelmed the cities of Herculaneum and 
Pompeii, we can readily admit that the number of volcanic vents 
or craters is much greater than really is now apparent. The im- 
mense height of the volcanic mountains of the Andes and Cor- 
dilleras is very remarkable, and the craters are all formed by 
bursting through porphyritic rock, or igneous unsiratified rock, 
containing crystals of feldspar. Some of the loftiest summits are 
composed of trachyte, a rock of igneous origin, unstratified and. 
allied to the trap rocks, such as basalt, greenstone, &e. On the 
summits are found large quantities of obsidian, or dark green vol- 
canic glass, pumice stone, and tuff formed out of cinders, and 
fragments of lava cemented together. 

It appears highly probable that a chain of volcanic vents ex- 
tends quite around the globe, in the general direction north and 
south. A lofty chain of mountains was discovered by Capt. J. 
C. Ross, in the Antarctic regions in year 1841, at a distance of 






VOLCANOES. 23? 

about 803 miles from the south pole. Two of the loftiest of these 
Were named from his vessels, Mount Erebus, and Mount Terror, 
they are each about 12,000 feet in height, and the former is an 
active volcano. This range of mountains is probably connected 
by a submarine chain with the Andes, first appearing in Terra- 
del-Fuego, near which Capt, Basil Hall is said to have witnessed 
volcanic eruptions. As we proceed north along the western shore 
of South America, we find in Chili, a large number of active 
volcanoes, and, what we might reasonably expect, the country 
continually disturbed by earthquakes, and abounding in hot 
springs. Villarica is the principal of the Chilian volcanoes, it 
burns without intermission, and is so high that it may be seen at 
a distance of 150 miles. It is said that a year never passes in 
this province, without some slight shocks of earthquakes, and 
sometimes the most tremendous convulsions occur. As we pro- 
ceed northward, we find one active volcano in Peru, but earth- 
quakes are so common that scarce a week passes without them ; 
and the names of Lima, and Callao, are familiar in this connect- 
ion. Proceeding still farther north, the mountains increase in 
height, and furnish by the melting of their accumulated snows, 
and the mois'ture which is precipitated from the trade winds which 
blow over the warm region of Brazil, the sources of that magni- 
ficent river, the Amazon, which continually pours such a flood of 
water into the Atlantic. When we arrive in the neighborhood of 
Quito, in Equador, we find numerous and very lofty volcanoes, 
no less than six being embraced in a space of five degrees ; com- 
mencing at the second degree of south latitude, and proceeding 
to the third degree of north latitude — One of these volcanoes, 
Cotopaxi, arises to the height of 18,867 feet, and is the highest 
volcanic summit of the Andes. Inform it is a perfect cone, us- 
ually covered with an enormous bed of snow. On next page, we 
give an engraving which represents this celebrated volcano, which 
is higher than Vesuvius would be, if placed on the top of TenerifTe. 
The smooth cone, crested with the purest white, shines in the 
rays of the sun with dazzling splendor, and detaches itself from 
the azure vault of heaven in the most picturesque manner. At 
night, smoke and fire are seen rising from its summit, like a 



238 THE WORLD. 

beacon of flame in the regions above. In the course of the last 
century it had five great eruptions; in one of these, in January 




1803, the snows were dissolved in one night, pouring a deluge of 
waters over the plains below. It is averred that the eruptions 
of Cotopaxi have been heard at a distance of 600 miles, and 
Humboldt states that at 140 miles distance on the coast of the 
Pacific, it sounded like thunder. The substances ejected from 
these lofty craters are pumice, and cinders, rarely lava currents; 
on account of their immense heights, and the consequent enor- 
mous pressure which is required to raise a solid molten mass. 
Torrents of mud and boiling water are erupted, and subterranean 
cavities containing water are opened, and vast quantities of mud, 
volcanic sand, and loose stones, are carried down to the regions 
below. Mud derived from this source, in the year 1797, descend- 
ed from the sides of Tunguragua, a volcano in the neighborhood 
of Cotopaxi, and filled valleys 1000 feet wide to the depth of 600 
feet. In these currents and lakes are thousands of small fish, 
which, according to Humboldt, have lived and multiplied in the 
subterranean lakes. So great a quantity of these fish were erupt- 
ed in 1690, from the volcano of Imbaburu, that fevers were caused 
by efnuvia arising from the putrid animal matter. Sometimes,after 
successive eruptions, the undermined walls of the mountain fall, 
and it becomes a mass of ruins, such was the fate of L'Altar, which 
was once higher than Chimborazo, but according to the tradition 
of the natives, before the discovery of America, a prodigious 
eruption took place which lasted eight years and broke it down. 



VOLCANO] 239 

In 1696 another lofty volcano fell, with a tremendous crash. 
Proceeding farther north, we find three active volcanoes in the 
province of Pasto, and three likewise in that of Popayan. Pass- 
ing on, across the isthmus of Darien into Guatemala, and Nicar- 
agua, no less than twenty-one active /olcanoes are found between 
the tenth and fifteenth degrees of noi th latitude. Among these 
is an enormous mountain called the volcano of water (dc AguaJ, 
at the base of which in 15*27, the old city of Guatemala was built. 
A few years afterward, a most formidable aqueous eruption burst 
forth, which overwhelmed the whole city, and buried in the ruins 
most of the inhabitants. Appalled by this disaster, the Spaniards 
built another city, New Guatemala, in another situation, farther 
from the mountain. Among other splendid buildings it contained 
a Cathedral more than 300 feet long, and one of its nunneries had 
more than 1000 persons in it. After a series of dreadful shocks, 
and volcanic eruptions, this beautiful city shared the fate of the 
former, and was reduced to a heap of mins in 1775. We have 
now traced this volcanic chain for a distance of nearly 5000 miles 
from south to north, arriving at the high (able land of Mexico, 
which is the middle part of the great chain of mountains called 
the Andes or Cordilleras in the south, and the Rocky Mountains 
in the north. This table land is from 6000 to 8000 feet in height, 
thus rivalling Mount St. Bernard and other remarkable summits 
in the eastern continent. This table land is not an interval be- 
tween opposite ridges, but is the highest part of the ridge itself. In 
the course of it, isolated peaks occur, the summits ot which reach 
the elevation of perpetual snow. It is somewhat remarkable, 
that a chain of volcanic mountains traverses this table land at right 
angles, which, with few interruptions, seems almost as smooth as 
the ocean, to a distance of 1500 miles north. Hence while com- 
munication with the City of Mexico is very difficult from either 
sea coast, there is nothing to prevent wheel carriages from run- 
ning along the top of this mountain chain to Santa Fe. The 
volcanic mountains, are five in number, and run at right angles; 
commencing with the most eastern, w T e have Tuxtla, a few miles 
west of Vera Cruz ; Orizava, the height of which is 17,370 feet; 
Popocatepetl 500 fact hig-her, and shown in the pngravinsr below. 



240 



THE WORLD. 



This is the highest mountain in Mexico, and is continually burn- 
ing. The two others lie on the western side of Mexico^and are 




called Jorullo and Colima, the latter being 9000 feet in height. 
We shall have occasion to speak of Jorullo and its eruptions 
hereafter. It is somewhat remarkable that these five volcanoes 
now active, are connected by a chain of intermediate ones, which 
undoubtedly have been so at some remote period, and that if the 
line ot volcanic vents be prolonged in a westerly direction, it will 
pass through a group of volcanic islands, called the isles of Rev- 
illagigedo. Proceeding north of Mexico, another chain of moun- 
tains running parallel with the Rocky Mountain chain, com- 
mencing in the peninsula of California, runs as far north as the 
50th deg. of north latitude, where it ends near the Rocky Moun- 
tains. In the peninsula of California there are three, or accord- 
ing to some accounts, five active volcanoes. In the Rocky 
Mountain chain from Mexico north, no active volcano occurs, 
but the whole country, says Mr. Parker, "from the Rocky Moun- 
tains on the east and Pacific Ocean on the west, and from Queen 
Charlotte's Island on the north to California on the south, presents 
one vast scene of igneous or volcanic action. Internal fires ap- 
pear to have reduced almost all the regular -rock formations to a 
state of fusion, and then, through fissures and chasms of the 
earth, to have forced the substances which constitute the present 
volcanic form? Such has been the intensity aud extent of this 



ROCKY MOUSTAINS. 



m 



acrencv, that mountains of amygdaloid and basalt have been 
thrown up : and the same substance is spread over the neighbor- 
ing plains, to what depth is not known ; but from observations 
made upon channels of rivers and the precipices of ravines, it is 
evidently very deep. The tops of some mountains are spread out 
into horizontal plains, some are rounded like domes, and others 
terminate in conical peaks and abrupt gminences of various mag- 
nitudes, which are numerous, presenting themselves in forms 
resembling pillars, pyramids, and castles. There are several 
regularly formed craters : but these, presenting themselves in 
depressions or in cones, are rendered obscure by the lapse of 
time." Mr. Parker also states that nearly all the rocks of this 
region are amygdaloid, i. e. a trap rock in which agates and mine- 
ral substances are scattered about like almonds in a cake: basalt, 
lava, and volcanic glass, or obsidian. The Rocky Mountain chain 
extends north to the Arctic ocean, skirts along its coast, and is 
probably connected subterraneously, with the volcanic band which 
we shall presently describe, extending from the Aleutian Isles, or 
extremity of the peninsula of Alaska, in Russ.'an America, to the 
Mc'uica Isles. The whole shore of western America, from the 
peninsula just mentioned to Vancouver's Islands, presents a bold 
and awful aspect, being: bordered with mountainous steeps, cov- 
ered with primeval forests, and containing two of the most 
elevated peaks in the northern part of America, Mount St. Elias, 
1?, 030 feet, and Mount Fairweather, 14,913 feet above the ocean. 
Passing from the peninsula of Alaska, we find the volcanic chain 
extending through the Aleutian or Fox Islands, which are a long 
and numerous group extending nearly to Kamschatka. From al- 
most every island, steep and lofty peaks arise, and from many, 
volcanic fire is discharged. In 1795 an island was thrown up and 
added to this group, by an eruption from beneath the sea, and con- 
tinued to increase, till in 1807 it measured twenty miles in circuit. 
Throughout this whole tract, earthquakes of the most terrific de- 
scription occur. The line of volcanic craters continues through 
the southern extremity of Kamschatka, where are seven active 
volcanoes, which in some eruptions have scattered ashes to im- 
mense distances. The chain fa prolonged through the Kurile 



&42 THE WORLD. 

islands, where a train of volcanic mountains exists, nine of which 
are known to have been in eruption ; and elevations of the bed 
of the sea from earthquakes have occurred several times since 
the middle of the last century. The line is next continued through 
the Japanese group, which contains a number of active volcanoes 
and is continually liable to earthquakes. Proceeding southward, 
the chain is continued through the islands of the East Indian 
Archipelago. Mountain ranges of a volcanic character traverse 
almost all these, some rising upwards of 12,000 feet in height. 
In Sumatra, four volcanoes occur, and also several in Java. The 
largest of the Mollucca group, Celebes, contains a number of 
volcanoes in a state of activity, and one of the most terrible erup- 
tions ever recorded happened on the island of Sumbawa another 
of this group. Here the chain branches off eastward and west- 
ward, passing to the west through New Guinea, New Britain, the 
Solomon group, and the New Hebrides, thence through the Friend- 
ly and Society Islands nearly east. Indeed the Pacific Ocean in 
the equatorial regions seems to have been one vast theatre of ig- 
neous action, its innumerable archipelagos being composed of 
volcanic rocks, or coralline limestones with active vents here 
and there. To the westward, the chain passes through Borneo, 
and Sumatra, to Barren Island in the Bay of Bengal. From 
Java southward, the chain may be traced along the coast of New 
Holland and Van Diemens land, and thence probably is a sub- 
marine connection with Freeman's Peak, in the Ballerny Isles, on 
the Antarctic continent. Still farther south we have the chain 
extending along Victoria land, between 80° and 70° of south 
latitude, connecting with Mounts Erebus and Terror before men- 
tioned. Another great chain of mountains runs nearly east and 
west from the shores of the Caspian sea to the Atlantic, passing 
through Turkey, Austria, Italy, Switzerland, France, and Spain. 
The whole region along this chain, which sends off many lateral 
branches, is subject to earthquakes and other volcanic phenomena; 
the well known volcanoes Etna, and Vesuvius, are a part of this 
chain. In addition to the volcanic chains we have named, there 
are some cases of isolated volcanic action, such as Mount Hecla 
in Iceland, and the volcanoes of Madagascar. 



IGNEOUS CAUSES OF CHANGE. 243 



CHAPTER VII. 

Volcanic Eruptions. 

" But, even then, the ground 
Heaved 'neath their tread — the giant turrets rocked, 
And fell : and instantly black night rushed down, 
And from its bosom burst a thunderous crash 
Stunning and terrible." Wm. Howitt. 

The number of active volcanoes, and solfataresor vents, from 
which sulphureous and acid vapors and gases are given off, is 
about 305; of these, 196 are in islands, and the other 109, are on 
continents. It is howevor, a remarkable fact that a majority of 
them are located near the ocean, or large bodies of water; and 
even submarine volcanoes are not of unfrequent occurrence. Be- 
sides the volcanoes now in action, there are many undisputable 
extinct volcanoes, i. e., volcanoes which at some period of the 
earth's existence, but before the historic era, have been in the 
state of active eruption. In no country is there better evidence 
of this than in France. There are in the districts of Auvergne, 
Vivarais, and Cervennes, more than a hundred conical moun- 
tains, composed of lava, scorise, and volcanic ashes heaped up, 
many of them still retaining their ancient craters, and in some 
cases currents of lava may be traced to great distances. The 
evidences of volcanic action in the Rocky Mountains we have 
already alluded to. 

How long a period of repose may be necessary to constitute an 
extinct volcano, is of course undetermined. We include as such, 
those which show indubitable evidence of former activity, but 
which have not had eruptions within the historic era. It is by no 
means necessary that volcanoes, to be considered active, should 
incessantly emit flames, they may remain for ages choked up, 



244 THE WORLD. 

and again suddenly resume all their former character. Thus 
Vesuvius, which had been extinct from time immemorial, al- 
though its crater was clearly formed by some ancient volcanic 
action; suddenly rekindled in the reign of Titus, and buried the 
cities of Herculaneum, Pompeii, -and Stabise, under its ashes. 
After this effort it again slumbered, the memory of its former 
power faded away; trees and grass grew on its summit, when sud- 
denly in 1630, it renewed its action. At this time, the crater, 
according to the account of Bracini, who visited Vesuvius not 
long before the eruption of that year, " was five miles in circum- 
ference, and about a thousand paces deep; its sides were covered 
with brush wood, and at the bottom there was a plain on which 
cattle grazed. In the woody parts wild boars frequently harbored. 
In one part of the plain, covered with ashes, were three small 
pools, one filled with hot and bitter water, another salter than the 
sea, and a third hot but tasteless." Suddenly, in December 1630, 
these forests and grassy plains were blown into the air, and their 
ashes scattered to the winds ; seven streams of lava poured at the 
same time from the crater, and overflowed several villages at the 
foot, and on the side of the mountain; since that time there has 
been a constant series of eruptions. Etna after slumbering for 
ages, burst forth and destroyed the city of Catania; the accounts 
of its previous eruptions having been considered by the inhabit- 
ants as fables. 

Subterranean noises, and the appearance, or increase of smoke, 
are the first symptoms of approaching volcanic action. This is 
soon accompanied by a trembling of the earth, and louder noises; 
the air darkens, and the smoke, thick with fine ashes, increases. 
The stream of smoke rises like an immense black shaft, high up 
into the air, and arriving at a point where its density is the same 
as the atmosphere, spreads out like a vast umbrella, overshadow- 
ing the whole country with its dark gloom. Such was the ap- 
pearance as described by Pliny, the Elder, who witnessed the 
eruption of Vesuvius which overwhelmed Pompeii, in A. D. 79. 
Occasionally, lightning flashes illuminate the dark cloud, and 
streams of red hot sand, like flames, shoot up into the sky, at- 
tended with loud explosions. The shocks, and tremblings of the 



VOLCANIC ERUPTIONS. 245 

ground, increase, and the whole neighborhood gives evidence of 
the immense pressure which is being exerted; presently the mol- 
ten lava, is by the immense force raised into the crater, and fill- 
ing it up, or melting its passage through the side, flows in a red 
hot stream down the flanks of the mountain in a river, or rather 
a torrent of fire. The eruption is sometimes attended with enor- 
mous currents of water, mud, and noxious gasses. A period of 
rest succeeds, generally of short duration; again the same phe- 
nomena are repeated, and thus the action continues for a varia- 
ble length of time, until finally, the crisis is past and the volca- 
no resumes its original quiet. 

The substances principally ejected by volcanoes are smoke, 
ashes, sand, scoria?, volcanic glass and bombs, and masses of 
rock. The ashes thrown out in volcanic eruptions appear to be 
the substance of the lava very finely divided. These ashes are 
raised so high that they are carried by the winds to almost incred- 
ible distances. Ashes from the eruption of a volcano in St. Vin- 
cent in 1812, were carried twenty league*, and fell in Barbadoes, 
and from the eruption of Hecla in 1766, they fell in Glaumba, a 
distance of fifty ieagues; and it is said that ashes from Vesuvius 
have fallen in Constantinople, a distance of four hundred and 
fifty leagues. The volcanic sand, is composed of particles some- 
what larger, but of the same character as the ashes, being commi- 
nuted particles of lava, and forming a principal part of ihe eject- 
ed matter of volcanic eruptions. Scoria?, and pumice stone, are 
cunsed by the gasses, which bursting through the melted lava, 
carry up with them certain portions into the atmosphere, which 
becoming consolidated, present the appearance so well known 
under the name of slag and cinders. Volcanic glass or obsidian, 
is often ejected in small melted masses ; sometimes, the winds 
catching this, spin it *nto the finest threads. We have seen many 
specimens of this kind Irom the eruptions of Kirauea, in the 
Sandwich Islands. Among the extinct volcanoes of France* 
drops, tears, aud eloncrated spheroids, b^ing drops of lava thrown 
out, and consolidated in the air, are continually found, they are 
called volcanic bombs. Masses of rock are always ejected in 
severe eruptions; in many cases these are undoubtedly torn ofT 



246 THE WORLD. 

from the interior of the mountain by the immense power exerted; 
and they are ejected without having been- melted. A stone of 
109 cubic yards in volume, was ejected by Cotopaxi, and thrown 
to a distance of nine miles. 

The force which is exerted, to cause the eruptions of lavas, or 
liquid masses of stone, is almost beyond belief, varying according 
to the height of the crater. The force of Vesuvius in some of 
its eruptions has been estimated as equivalent to a pressure of at 
least 6000 pounds on every square inch ; and of Etna, about 17,- 
000 pounds on the square inch ; the amount of force requisite to 
raise melted lava to the crater of Cotopaxi, would be at least 30,- 
000 pounds on each square inch. The masses of melted matter 
ejected, are equally incredible ; the amount thrown out by Vesu- 
vius in 1737, was estimated at 11,839,168 cubic yards, and about 
twice this amount in 1794. In 1660, the mass of matter disgorged 
by Etna, according to Mr. Lyell, was twenty times greater than 
the whole mass of the mountain, and in 1669, when 77,000 per- 
sons were destroyed, the lava covered 84 square miles. The 
greatest eruption of modern times, was from Skaptar Jokul, in 
Iceland, in 1783. Two streams of lava, one fifty miles long and 
twelve broad, the other forty miles long, and seven bioad ; both 
avaraging 100 feet in thickness, and sometimes 500 or 600 feet, 
flowed in opposite directions, destroying twenty villages, and 
9000 inhabitants. The velocity with which the melted lavas move 
varies with the slope of the mountain, and the nature of the 
ground, as well as the viscidity and quantity of the lava. In 
general, a velocity of 400 yards an hour is considered quick, al- 
though sometimes the stream flows much quicker; in flat grounds 
it sometimes occupies whole days in moving a few yards. Lavas 
cool extremely slow, the surface becomes soon consolidated, and 
i.s such a poor conducter of heat, that the interior remains heated 
and melted for whole years ; and currents have been mentioned 
which were flowing ten years after emerging from the crater, 
and they have been seen smoking twenty years after an eruption 
of Etna. The currents of lava thrown out by successive erupt- 
ions being placed one above the other, alternating with beds of 
sand, scoriae, &c, form a series of inclined beds that give rise to 
the cone of the mountain. 



HERCtfLANEUM and POMPEII. 247 

Having now described the principal phenomena attending vol- 
canic eruptions, and the nature of the erupted materials, we pro- 
ceed to describe briefly some of the more remarkable effects of 
volcanic agency. Southern Italy, being inhabited by a cultivated 
people, and in very early times the scat of literature and science, 
as well as the grand European seat of volcanic action, claims 
particular attention. Here are three active volcanic vents. Ve- 
suvius near Naples, Stromboli on the Lipari Isles, and Etna in 
Sicily. The whole region is subject to earthquakes, and abounds 
in thermal springs impregnated with calcareous matter, and from 
certain fissures deleterious gasses and sulphureous flames issue. 
The ancient name of Vesuvius, was Somma; it is now a broken 
and irregular cone about 4000 feet in height. We have already 
given the description of this mountain as it appeared before the 
eruption of 1631. It is said that its cone was formerly of a regu- 
lar shape, with a flat summit, containing the remains of an an- 
cient crater, and covered with wild vines. After a slumber of 
ages, Vesuvius in the year 63, began to exhibit some symp- 
toms of internal agitation, by an earthquake which occasioned 
considerable damage to some of the neighboring cities. It is 
somewhat remarkable that the memorials of this convulsion 
have been preserved, and made known, through the agency of 
another more terrible convulsion, that of August 24th in the year 
79, when a tremendous eruption occurred, and the pent up melt- 
ed materials of the volcano burst out, overwhelming three cities 
and many of their inhabitants. Two of these cities, Herculane- 
um, and Pompeii, have since been exhumed. The former was 
first discovered ; but they had long been forgotten. The eruption 
which destroyed these cities was witnessed by both the Plinys, 
and indeed, it was from his too venturesome curiosity to observe 
this magnificent natural exhibition, that the elder Pliny lost his 
life, being suffocated by the sulphureous vapors. The account 
which Pliny the Younger has left of this eruption, is very full 
and minute ; but he makes no allusion to the overwhelming of 
the two cities. In 1713, Herculaneum was accidentally discov- 
ered, having been buried in lava for 1634 years. Some frag- 
ments of marble were observed in sinking a well; and subse- 



248 THE WORLD. 

quently a small temple, and some statuary. The city of Portici 
is built upon the lava directly above Herculaneum, and this has 
prevented extensive excavations. Pompeii was enveloped in ashes 
and cinders, and has been opened to the light of da}*. Both these 
cities were sea-ports, and Herculaneum is still near the shore, 
but Pompeii is at some distance, ihe intervening land having been 
formed by volcanic agency. In both these cities inscriptions were 
found in the temples commemorating the event of their rebuild- 
ing after having been overthrown by an earthquake sixteen years 
before, A. D. 63. Thus, in the language of Buhver, "After nearly 
seventeen centuries had roiled away, the city of Pompeii was dis- 
intered from its silent tomb, all vivid with undimmed hues ; its 
walls fresh as if painted yesterday; not a tint faded on the rich 
mosaic of its floors; in its forum the half-finished columns, as 
left by the workman's hand ; before the trees in its gardens the 
sacrificial tripod; in its halls the chest of treasure; in its baths the 
strigil; in its theatres the counter of admission; in its saloons the 
furniture and the lamp; in its triclinia the fragments of the last 
feast; in its cubicula the perfumes and rouge of faded beauty; 
and everywhere the skeletons of those who once moved the 
springs of that minute, yet gorgeous machine of luxury and of life." 




We here present a view of Vesuvius from Sir Win. GeJls Poin- 



ERUPTIONS OF ETNA. 249 

peiana, showing tiie site of Pompeii, and the course of the river 
Sarnus. Among the ruins of these cities many valuable relics 
have been found. The various utensils and works of art, almost 
as fresh as though buried but for a day. Rolls of papyri, with 
little tickets attached, denoting their contents; loaves bearing the 
stamp of the baker; linen, and fish-nets, and fruits, all preserved 
along with sculptures, and paintings, and unharmed for near 2000 
years. No doubt, many valuable manuscripts will be found when 
Herculaneu m is more excavated, which will restore to us the lost 
writings of the ancient philosophers. The eruption of Vesuvius 
w T hich buried these cities, is so well known we need not dwell 
longer upon it here : we pass to consider next the eruptions of 
Etna. 

The cone of Etna, which has been so minutely and well de- 
scribed by Mr. Lyell, is entirely composed of lavas, and rises 
•majestically to an altitude of two miles, the circumference of its 
base being about 180 miles. At the base of the mountain is a 
delightful, well cultivated and fertile country, thickly inhabited, 
and covered with olives, vines, corn, fruit trees, and aromatic 
herbs. Higher up, upon the mountain side, a woody belt encir- 
cles ii, forming an extensive forest of chesnut, oak, and pine, 
with some groves of cork and beech, and affording excellent pas- 
turage for flocks; still higher up, is a bleak barren region, cover- 
ed with dark lavas and scorice. Here, from a kind of plain arises 
the cone of Etna to the height of 11,000 feet, and continually 
emits sulphureous vapors ; its highest points being covered with 
eternal snow. Over the flanks of Etna a multitude of minor 
cones are distributed, particularly in the woody tract, caused by 
former eruptions, but the grandest feature of Etna is the Vol del 
Bove, which is a vast excavation, as though a portion of the 
mountain had been removed on the side towards the sea, forming 
a vast plain, five miles across, encircled by minor volcanic cones, 
and enclosed on three sides by precipitous rocks from 2000 to 
3000 feet high. This vast plain has been repeatedly deluged by 
streams of lava, and presents a surface more rugged and uneven 
than that of the most tempestuous sea. From the earliest period 
of history, Etna appears to have been active, but the first great 



250 THE WORLD. 

eruption of modern times occurred in the year 1669. Previous 
to this eruption, an earthquake occurred which levelled many of 
the villages and towns in the neighborhood, and was attended 
with an extraordinary phenomenon* A fissure, six feet broad and 
of unknown depth, opened with a loud crash in the plain of St* 
Lio, and run to within a mile of the summit of Etna* in a some- 
what tortuous course* Its direction was from north to south, and 
it emitted a most vivid light. Five other parallel fissures of con- 
siderable length, afterwards opened, one after another, attended 
with similar phenomena. Mr. Lyell supposes that these were, at 
the time, filled with melted trap or porphyry, forming vertical 
dikes. During this eruption a minor cone known by the name 
of Monti Rossi, was formed, about 450 feet high, which poured 
out a lava current, which after overflowing some fourteen towns 
and villages, some having a population of 3000 to 4000 inhabit- 
ants reached the city of Catania, ten miles distant from the vol- 
cano. Walls sixty feet high had been purposely raised to pro- 
tect the city in case of eruption. Against this rampart the lava 
flowed, and accumulated, until in a fiery cascade, it poured over 
the top, and destroyed a part of the city* The wall still remains, 
and the curious traveler may see the lava curling over the top, 
by means of excavations since made, as if still in the very act of 
falling. This lava current move.d a distance of fifteen miles be- 
fore it reached the sea. One of the towns overflowed during this 
eruption was Mompiliere, a part of which, was afterwards un- 
covered with incredible labor, and the gate of the principal 
Church was reached at a depth of thirty-five feet, and several ar- 
ticles in good preservation were extracted, among these were a 
bell, a statue, and some coins. It is said that the heat of this lava 
current was so intense eight years afterwards, that it was impos- 
sible to hold the hand on some of the crevices formed by the 
cracking of its crust upon cooling. In the year 1828 a remarka- 
ble discovery of a glacier covered by a lava stream was made, 
after having been concealed for ages. In that year, from the pro- 
tracted heat of the season, supplies of ice at Catania and the ad- 
joining parts of Sicily, failed entirely, and great distress was felt 
at the want of a commodity which they had learned to* regard as 



LKlriIO;o 01 11ECLA. 2i& 

& necessary of life; accordingly search was made at a place which 
had long been suspected as being a glacier covered with lava, at 
the foot of the highest cone, when for several hundred yards a 
solid bed of ice, so hard that it was quarried with the utmost dif- 
ficulty was found, covered entirely by lava. 

We now turn to Iceland, an island subject to tremendous vol* 
canic eruptions, and containing several volcanic mountains* 
Mount Hecla has been in continual activity, with but a short oc- 
casional rest, from the earliest period ; its eruptions have lasted 
sometimes as long as six years without cessation. In the year 
1783 two great eruptions happened, about a month apart, one 
about the middle of May, and the other the 11th of June. The 
first was a submarine volcano which threw up so much pumice 
that the ocean was covered to a distance of 150 miles. A new 
island was formed, consisting of high cliffs, within which, fire, 
smoke, and pumice, were emitted from several different parts* 
This island, which, was claimed by his Danish Majesty and called 
Nyoe, or new-island, was destroyed before a year, by the sea 3 
leaving nothing but a reef of rocks from five to thirty fathom* 
under w T ater. The eruption of June 11th was on the island, a 
distance of 200 miles from Nyoe, when the crater of Skapta Jokul 
emitted a torrent of lava which flowed dowm into the river Skap- 
ta, and entirely dried it. This river was about 200 feet in breadth 
and from 400 to 600 feet deep, running between high rocks, not 
only was this great bed filled with the lava current, but, rising 
higher, it overflowed the neighboring fields; after filling the bed 
of the river, the lava current flowed into a deep lake, which was 
in a short time completely filled; still flowing on, it penetrated 
the caverns which had been formed in the older lava, and melted 
down portions of it, and in some cases where it could not ge t 
vent, it blew up the rock with a tremendous explosion. On the 
18th of June another ejection of melted lava, flowed with great 
swiftness down the mountain, over the bed of the former erupt- 
ion. " By the damming up of the rivers, and lakes, and conse- 
quent displacement of water, many villages were completely de- 
stroyed and overwhelmed* This lava current, after flowing for 
several dap, was finally precipitated down a tremendous catar- 



%&% THE WORLD* 

act called Stapafoss, filling up a profound abyss which the water 
had been hollowing out for ages. On the 3rd of August another 
flood of lava was poured forth which flowing in an entirely new 
direction, as all the other channels were choked up, filled the bed 
of the river Hverfisfliot, occasioning great destruction of property 
and life. The eruption continued for about two years, and eleven 
years afterwards when Mr. Paulson visited the island, he found 
columns of smoke still rising from parts of the lava, and several 
rents filled with hot water. Iceland at this time contained about 
50,000 inhabitants, more than 9000 of whom perished during 
these eruptions, besides vast numbers of cattle; and twenty villa* 
ges were destroyed, not enumerating those inundated by water. 
The great loss of life was owing not only to the vast amount of 
noxious gasses emitted, but to the famine caused by the showers 
of ashes throughout the island, and the desertion of the coasts by 
the fish. The two branches of lava which flowed during this 
eruption, in opposite directions, were, the one fifty, the other forty 
miles in length, and their average depth 100 feet. The extreme 
breadth of the current which filled the bed of the river Skapta, 
was twelve miles, the extreme breadth of the other was about 
seven miles. The eruptions of Hecla, six of which have occurred 
in one century, seem now to be suspsnded, but the whole island 
presents abundant evidence of volcanic action. We have already 
alluded to the phenomena of the Geysers, or hot springs; beside 
these there are no less than six volcanic vents, emitting flame 
and smoke. The island of Nyoe thrown up just before the great 
eruption of Skapta Jokul, is by no means the only instance of a 
volcanic island occurring at a recent period. In the year 1831, a 
volcanic island arose in the Mediterranean, about thirty miles off 
the south-west coast of Sicily, in a spot which had been found by 
CapU Smyth to be more than 600 feet in depth. On the 28th of 
June, Sir Pultney Malcolm, in passing over the spot with his ship 
felt the shock of an earthquake, as if he had struck on a sand 
bank, this was about a fortnight before the eruption occurred. 
About the 10th of July a Spanish Captain who was passing near 
the plaoe, reported that he saw a column of water, like a water 
spout, about sixty feet in height, rising from the sea; this was 



YOLC\NIC ISLAND. 



253 



succeeded by a cloud of steam, and at length, on his return, the 
18tli of July, he found a small island about twelve feet high, with 
a crater in its centre, ejecting sconce, ashes,,- and volumes of va- 
por; and the sea around was covered with floating cinders, and 
dead fish. This island continued increasing in dimensions until 
it reached an elevation of 200 feet, and was about three miles in 
circumference, having a circular basin full of hot water, of a din- 
gy red color. The eruption continued with great violence nearly 
a month, and the island attained its greatest dimensions about 
the 4th of August, after which it began to decrease by the action 
of the waves, and on the 29th of September, its circumference 
was reduced to about 700 yards. Its appearance at this time is 
represented in the accompanying wood cut, which is from a sketch 




by M. Joinville, who visited this island in September 1831. It 
has now entirely disappeared, and a dangerous shoal remains 
about eleven feet .under water. This is not the only volcanic island 
of recent formation, for in the year 1812, off the coast of St. 
Miclicel's one of the Azores, an immense volume of smoke, 
thick with ashes and stones, was observed to burst forth, by Capt. 
Tillard, of the Royal British Navy, at a spot where before, the 



^54 THE W0H2.D. 

water was thirty fathoms in depth, At the same time the cliffs 
of St. Michael were shattered by an earthquake. This island 4 
which was called Sabrina, from the ship of Capt. Tillard, rose 
200 feet above the water, but soon after disappeared being com- 
posed almost entirely of ashes and cinders. We have already 
noticed the Aleutian islands, as the theatre of volcanic action. In 
the year 1806, a new island, which still remains, and consists of 
solid rock, about four miles in circumference, was thrown up from 
the bottom of the sea; and in 1814, another of the same charac- 
ter, but much larger, being 3000 feet in height, was added to the 
same group. We might enumerate many other islands formed by 
volcanic agency did our limits permit, but we hasten to consider 
next the volcanoes of South America. 

In noticing the great chain of mountains which runs along the 
western coast of America, we alluded to the five volcanic vents 
in about the parallel of the City of Mexico, arranged in a line at 
right angles nearly to the general direction of the mountainous 
chain. One of these volcanoes, that of Jorullo, is particularly 
remarkable, being the product of an eruption which occurred in 
1759, and lasted about nine months. The volcanoes of Tuxtla, 
Orizava, and Popocatapetl, are on the eastern side of Mexico, the 
latter is continually burning, but seldom emits anything more 
than smoke and ashes. At the west of the city, are the volcanoes 
of Colima, and Jorullo, the former about 9000 feet in height, and 
emitting smoke and ashes; between the city and this volcano lies 
the plain of Jorullo, in which a crater was formed in 1759. In 
that year according to Humboldt, who has minutely described the 
phenomena, in the month of June, a subterranean noise was 
heard in the district of Jorullo; hollow sounds of the most fright- 
ful nature, which were accompanied by frequent earthquakes, 
succeeded each other for from forty to fifty days ; causing great 
terror to the inhabitants of that district. From .the beginning of 
September everything seemed to announce the complete re- 
establishment of tranquility, when, in the night of the 28th and 
29th, the horrible subterranean noise recommenced. The af- 
frighted Indians fled to the mountains, soon a tract of ground, 
from three to four square miles in extent, began to swell like waves 



ERUPTION OF JORULLO. • 256 

of the sea, and finally rose up in the shape of a bladder, then 
opened, and fragments of burning rocks accompanied with flames, 
were thrown to an immense height. The rivers Cuitimbaand 
San Pedro, which watered this plain, formerly cultivated with 
fields of cane and indigo, precipitated themselves into the burn- 
ing chasms. Hundreds of small cones from three to ten feet 
high, called by the natives hornitos issued from the smoking plain, 
and six large volcanic cones wero formed, the smallest three hun- 
dred feet high, and the largest, which is the present volcano of 
Jorullo, 1600 feet in height. It is continually burning, or rather 
now sending forth sulphureous gasses, and has thrown up from 
its north side immense masses of basaltic lava, with fragments of 
granitic rocks. Below we give an outline of this celebrated vol- 




canic mountain, a is the summit of Jorullo, b c inclined plane, 
sloping at an angle of 6° from the base of the cones. This 
eruption occurred at a distance of 150 miles from the sea-coast, 
and is somewhat remarkable on this account, all other active vol- 
canoes being near the sea. The eruptions of mud, however, 
and balls of decomposed basalt, and especially strata of clay, 
seem to indicate that subterraneous water had no small share in 
producing this phenomenon. Humboldt visited the country more 
than forty years after the eruption, and found the elevated mass 
of the former plain, shown by the slope b c in the preceding out- 
line sketch, still hot enough in some of the fissures at a depth of 
a few inches, to light a cigar. The hornitos have now ceased to 
emit steam, or smoke, and the central volcano is itself almost 
extinct, the plain and slope of the mountain is covered with a 
luxurious vegetation, and the rnemory of the former terrific con- 
vulsions seems almost forgotten. 

We have now given an account of the most celebrated volca- 



256 THE WORLD. 

noes, and the effects produced by their eruptions. When we bear 
in mind that during the earlier periods of the earth's existence, 
volcanic action was much more genera] and severe than at pre- 
sent, we will be at no loss for a sufficient cause to produce most 
of the upheavings, and contortions of strata, observed on our 
globe. In some parts of the world, whole districts are composed 
of extinct volcanoes, which even yet have not wholly ceased to 
emit deleterious gasses, and the traces of their former and pow-^ 
erful action are seen in every country. 

We have not discussed at all, the causes which produce volca- 
nic eruptions ; these are not yet satisfactorily determined ; and a 
great diversity of opinion still exists among philosophers. It will 
be seen upon referring to the diagram, (page 178), that the com- 
parative height of the loftiest mountains, is but as a minute grain 
of sand on a large globe, and that such slight changes from the 
general level of the surface may be produced by causes compara- 
tively small. 






IGNEOUS CAUSES OF CHANGE. 257 



CHAPTER VIII. 

Earthquakes. 

" Of chance or change, oh! let not man complain ; 
Else shall he never, never, cease to wail ; 
For from the imperial dome, to where the swain 
Rears his lone cottage in the silent dale, 
All feel the assault of fortune's fickle gale. 
Art, empire, earth itself, are doom'd ; 
Earthquakes have raised to heaven the humble vale; 
And gulfs the mountains' mighty mass eutomb'd; 
And where the Atlantic rolls, wide continents have bloom'd." 

Beaitie. 

In the present chapter we shall briefly describe some of those 
remarkable convulsions which from time to time have caused the 
crust of the earth to heave like the waves of the ocean, and to 
gape open in many places, suddenly engulphing cities and their 
inhabitants, or deluging whole tracts of country by the upheaved 
waters. These phenomena, which are supposed to be caused by 
immense evolutions of steam, and other vapors, or gasses, under 
an intense pressure, which is only relieved by a volcanic erup- 
tion, or an opening of the earth, constitute the most terrible warn- 
ings, which reminds us of the instability of all things. The evi- 
dences of mighty change which the philosopher sees in each up- 
heaved hill of granite, and dike of trap, or in the formation of 
contorted strata may read to him a lesson, which, if rightly un- 
derstood, *will teach him to look far from his present abode, for 
the unchangable world; but the careless observer, who builds his 
cottage on the side of a volcanic cone, and feeds his flocks with- 
in its crater, needs the awful sound of subterranean thunder, and 
the rocking of the plain, to convince him that the neglected tra- 
ditions of former calamities, were not all a fiction. 



258 WORLD. 

There is something startling in the idea that our earth, or rath- 
er its crust, is perhaps but a few hundred miles in thickness, or 
in other words, that our globe is a hollow ball of no very great 
dimensions. It is a well established proposition that, under influ- 
ence of the attraction of gravitation, a body, or a mass of matter, 
placed any where within a hollow globe, as at a or b, (see the dia- 
gram below), will remain at rest wherever it may be situated. 




Hence, whether the interior of the hollow glob© be molten or 
not, the mass will not be displaced, or in other words, it will have 
no tendency to move, unless operated upon by other force than 
the attraction of gravitation. 

The name earthquake has been given to those convulsions of 
supposed igneous origin, which cause the surface of the earth to 
heave, or undulate, producing rents, and generally precursing the 
eruption of some volcano. The region of violent earthquakes, 
is generally the site of some active volcano, and the paroxysms 
of an earthquake, are generally relieved by a volcanic eruption. 
Thus, during the earthquake which overturned Lima in 1746, and 
which was one of the most terrible which has been recorded, four 
volcanoes opened in one night, and the agitation of the earth 
ceased. The phenomena attending earthquakes are* various, 
sometimes there is but a slight undulatory movement, barely suf- 
ficient to cause the lighter articles upon the surface to change 
places. Persons unacquainted with the phenomena of earth- 
quakes, suppose themselves seized with a sudden giddiness. Of- 
ten the first shocks are of this light character, then gradually be- 



PHENOMENA ATTENDING EARTHQUAKES. 259 

«ome more severe, and frequent, so that the movement of the 
earth is apparent to the most inexperienced. It is now that the 
subterranean thunder is heard, and the walls of buildings begiu 
to gape open, and close, rendering it exceedingly dangerous to re- 
main in them. The fields and the mountains, at such times, af- 
ford no secure shelter, the former are often rent asunder, open- 
ing enormous fissures, which engulph thousands, and then close 
again, while the mountains are rent, and slide down into the val- 
leys, damming up the rivers and lakes, and causing tremendous 
inundations. At such times, th.Q bed of the ocean appears as un- 
stable as the dry land; vast waves, sometimes fifty or sixty feet 
in height, are rolled along the coast, and then retire, leaving the 
whole shore dry. Ships at sea, often experience these extraor- 
dinary movements, even at a distance of 250 miles from land, 
seeming as violently agitated as though grating over a ledge of 
rocks, and suddenly striking on the ground, and often with such 
violence as to open the seams of the vessel. The duration of a 
single shock rarely exceeds half a second. In this short space of 
time, thousands of human beings have found a common grave, 
and whole cities have been swallowed up. The interval which 
-elapses between successive shocks is variable; sometimes they 
succeed with considerable rapidity, and at other times happen 
after an interval of months, or even years. The first shock is 
not always the most violent, though in some particular regions of 
country, Syria, for example, the first catastrophe is always the 
most destructive; generally however, the second shock is more 
violent. The extent of country agitated by some great earth- 
quakes is very remarkable; thus the momentary upheaving of the 
bed of the ocean, during the earthquake of 1755, which destroy- 
ed Lisbon, caused the sea to overflow the coasts of Sweden, 
England, and Spain, and the islands of Antigua, Barbadoes, and 
Martinique, in America; at Barbadoes, the tide rose nearly 18 
feet above high water mark, and the water was black as ink frojn 
£he presence of bituminous matter. On the 1st of November, 
when the concussions appeared most violent, the water at Gua- 
dalope retreated twice, and on its return rose in the channel of 
£he Island 10 or 12 feet in height. A wave of the sea, 60 feet 






260 th:e woblr 

high, overflowed a part of the city of Cadiz; ami the lake of Ge- 
neva was observed to be in commotion six hours after the shock; 
agitations were also noticed on lake Ontario. Such is the great 
extent of country influenced by these terrible convulsions when 
exhibited in their most destructive form, but the changes which 
are silently being accomplished, the gradual elevations and sub- 
sidences of the land are no less remarkable. Previously to noti- 
cing these however, we will allude for a moment to similar phe- 
nomena but accomplished suddenly. In the year 1772, during 
an eruption of one of the loftiest mountains in the island of Java,, 
a part of the island, and of the volcano, embracing a tract of 
country fifteen miles long, and six miles broad, was swallowed 
up, and in 1775, during the eruption which destroyed Lisbon, a 
new quay, upon which thousands of the affrighted inhabitants 
had congregated, suddenly disappeared, and not one of their bod- 
ies ever rose to the surface. In 1692, a tract of land a thousand 
acres in extent, in the island of Jamacia, sank down in less than 
a minute, and the sea took its place. On the 16th of June 1816, 
a violent earthquake happened at Catch, in Bombay, which so 
much altered the eastern channel of the Indus, that from having 
been easily fordable, it was deepened to more than eighteen feei 
at low water, and the channel of the river Runn which had some- 
times before been almost dry, was no longer fordable except at 
one place; and at the same time the mud village and fort of 
Sindree, belonging to the Cutch government, and situated where 
the Runn joins the Indus, was submerged, leaving only the tops of 
the houses above the water. But the subsidence of land caused 
by earthquakes is not more remarkable than the elevation, and 
many examples might be given of the upraising of land. Perhaps 
the most remarkable was during the terrible earthquake in No- 
vember 1822, which agitated the western coast of South Ameri- 
ca in the vicinity of Chili, for a distance of twelve hundred miles 
from north to south. On examining the district around Valpa- 
raiso the morning after the shock, it was found that the entire 
coast for upwards of one hundred miles was raised above its for- 
mer level, thus leaving dry the bed of the sea. The area of the 
surface upraised, and which extended horn the sea coast to th* 



TEMPLE 07 JUPITER SERAPIS. '261 

foot of the Andes, was estimated at one hundred thousand square 
miles. The rise upon the coast, was from two to four feet. In 
the year 1790 during several shocks, a space of ground three Ital- 
ian miles in circumference, sank down near the town of Terra- 
nuovo, on the south coast of Sicily. Such are some of the im- 
mense changes effected during violent earthquakes. ^Numerous 
examples of immense rents, and sinking" down of mountains 
might be cited did our limits permit, enough however, has been 
adduced, to show that the force which is sometimes generated 
far beneath the present surface of the earth, is almost beyond 
conception, far exceeding any pressure which human agency can 
produce. 

The elevation and subsidence of various lines of coast, deter- 
mined by water marks, but performed in a very gradual manner 
may be appropriately considered in this place. We commence 
with the beautiful Bay of Baiee, which the researches of Lvell, 
Babbage, and other eminent philosophers have rendered a doubly 
classic ground. On the golden shores of this beautiful bay, some 
pillars and other fragments of an ancient Roman building were 
long known to exist These were once supposed to be the re- 
mains of a temple dedicated to Jupiter Serapis, but the researches 




of modern antiquaries have rendered it probable that these relics 
are the ruins of an extensive suit of baths. Three of the pillars 
r- 



262 THE WORLD. 

of this supposed temple, are yet standing, and are represented in 
the wood cut. These pillars are of marble, carved from a single 
block, and forty-two feet in height. One of the columns has a 
horizontal fissure extending nearly through it, the others are en- 
tire. All are slightly out of the perpendicular, leaning towards 
the sea. On these pillars, graven in marks too palpable to be mis- 
interpreted, are characters which indicate that twice since the 
Christian Era the level of the land and sea has changed at Puz- 
zuoli, and each movement, both of subsidence and elevation has 
exceeded twenty feet. The surface of these pillars is smooth for 
a distance of twelve feet from the pedestal, where a band of perfo- 
rations made by a marine boring muscle or bivalve (HUwdomus*), 
commences and extends to a height of nine feet, above which, 
all traces of their ravages disappear. The holes are pear shaped, 
and in many of them shells are still found, notwithstanding the 
numbers carried off by curious visitors. The depth and size of 
these perforations indicate that the columns must have been sub- 
merged for a. long time; for the hole, which is at first very small, 
and cylindrical, is enlarged by the animal as its size increases 
Besides these perforations there are incrustations effected by the 
agency of thermal springs in the neighborhood, and at varying 
distances, showing the gradual submersion. From all the facts 
which have been collected, we may prove pretty conclusively, 
as Mr. Babbage has done, that the temple, or rather baths, which 
was originally a building of a quadrangular form, seventy feet in 
diameter, the roof being supported by twenty-four granite col- 
umns, and twenty-two of marble, was built near the sea for con- 
venience of the sea-baths, and also for the use of the hot spring 
which still exists on the land side of the temple; and that by the 
gradual subsidence of the lanH, a channel was formed, through 
which the salt water flowing and mingling with the thermal wa- 
ters, a brackish lake was formed, producing an incrustation at 
various heights, of from three to four and a half feet, of a differ- 
ent character from what either would produce separately. After 
this, the land still subsiding, the channel which admitted the sea 



* Lithodomus, from lithos a stone, anu domus a house. 

* 



TEMPLE OF JUPITER SERA PIS. 



263 



became choked by sand, tufa, and ashes, and also the area of the 
temple, and thus a lake of the waters of the hot spring was made 
the bottom of which would be very irregular, the proofs of this, 
are the incrustations of carbonate of lime, presenting a level sur- 
face above, but irregular below, and not covering the former in- 
crustations. The land still continuing to subside, the sea again 
encroached, when the lithodomi, attaching themselves to the col- 
umns, and fragments of marble, pierced them in all directions, 
and this subsidence continued until the pavement of the temple 
was nineteen feet below the bottom of the sea. The base and 
lower portions of the temple being protected by the rubbish and 
tufa, and the upper, projecting above the water, prevented the 
ravages of the lithodomi, on those portions. The platform of the 
temple is now about one foot below high water mark, and the sea 
is forty yards distant. It is clear therefore, that they have long 
been submerged, and again elevated, moving each time a distance 
of twenty-three feet, and yet by so gentle a motion that the col- 
umns have not been overthrown. Not far from the Jemple is the 
solfatara or volcanic vent opened in the year 1198, after a series 
of earthquakes, and it is highly probable that during these earth- 
quakes the land subsided, and the pumice and ashes ejected from 
the volcano falling into the sea protected the lower part of 
those columns which remained erect, from being bored by the 
lithodomi. The re-elevation was probably gradual at first, for we 
find in the year 1503, a deed from Ferdinand and Isabella, grant- 
ing to the University of Puzzuoli " a portion of land where the sea 
is -drying up;" but the principal -elevation took place in 1538, when 
the volcanic cone of Monte Nuovo was formed, at which time, 
according to the accounts of eye-witnesses, the sea left the shore 
dry for a considerable space. Great as have been the changes of 
elevation and depression of the shores of the Bay of Baiae, yet 
the movement has been so gentle as not to overthrow these an- 
cient remains, 

" Whose lonely columns stand sublime 
Flinging their shadows from on high 
Like dials, which the wizard Time 
Had raised to count his ages by." 



264 * THE WORLD. 

At the present moment the land is again subsiding and in th© 
same gentle manner. 

What was once deemed an encroachment, or rather a rise in 
the level of the sea, is now well understood to be but the move- 
ment of the coast, gently subsiding, this fact is well illustrated by 
the movement of land in Sweden, which is now, and has been 
for ages in course of elevation in some places, and depression in 
others, rising in the northern, and sinking in the southern parts. 
The proof of this great change, which had long been suspected, 
was complete upon examining the marks cut upon the rocks by 
the officers of the pilotage establishment of Sweden. It was 
found that in the space of fourteen years, the rise had been from 
four to five inches. The prevalence of marine shells, at some 
distance in the interior, of the same species as those now living 
m the neighboring seas, renders in highly probable that this rise 
has been going on for a long time, in certain portions of that 
country. The rocks of the coasts of Norway and Sweden, are 
pricipally gneiss, mica-schist, and quartz, and will retain their 
particular configuration or appearance unaltered for a long series 
of years, there seems therefore, but little room for any doubt as to 
the change of level of the land and sea, determined by the an- 
cient landmarks, the appearance of new shoals, the elevation of 
the lines cut to mark the height of the water years previous, and 
the abundant occurrence of marine shells attached to the rocks 
at the distance of even fifty miles from the sea coast. From some 
phenomena occurring near Stockholm, it would seem that the 
land has been depressed and then re-elevated. In the year 1819, 
in digging a canal at .Sodertelje, a place sixteen miles south of 
Stockholm, for the purpose of uniting Lake Maeler with the Bal- 
tic, at a depth of sixty feet, the workmen came upon what ap- 
peared to have been a buried fishing-hut, constructed of wood, it 
was in a state of decomposition, and crumbled away on exposure 
to the air. On the floor of the hut, which was in better preserva- 
tion, was a fire-place composed of a ring of stones, within which 
were found cinders and charred wood, and outside were boughs 
of fir, still retaining the leaves and bearing the marks of the axe. 
Besides the hut, several vessels of an antfque form were found, 



ELEVATION ©F SEA COASTS. 265 

having- their timbers fastened together with wooden pegs, instead 
of naita, indicating their great antiquity. The situation of the 
hut seems only to be accounted for on the supposition of a change 
similar to that on the shores of the Bay of Baiae, first subsiding to 
a depth of more than 60 feet, and subsequently being re-elevated. 
Examples of this gradual elevation are by no means rare. The 
coast of Newfoundland, in the neighborhood of Conception Bay, 
and probably the whole island is rising out of the ocean, at a 
rate which promises at no very distant period, materially to affect, 
if not render useless, many of the best harbors on its coast. At 
Port-de- Grave, a series of observations have been made, which 
undeniably prove the rapid displacement of the sea-level in the 
vicinity. Several large flat rocks, over which schooners might 
pass some thirty or forty years ago with the greatest facility, are 
now approaching the surface of the water, so that it is scarcely 
navigable for a skiff. Dr. Jackson describes a deposit of recent 
shells in clay and mud, with the remains of balani or barnacles, 
attached to trap rock twenty-six feet above the present high- water 
mark, on the margin of Lubec Bay in the State of Maine. 

Changes like these which we have just described, have been 
of universal occurrence. Upon this subject Cuvier remarks, 
•« The lowest and most level lands, when penetrated to a great 
depth, exhibit nothing but horizontal strata, consisting of various 
substances, almost all of them containing innumerable product- 
ions of the sea; sypiilar strata, similar productions, compose the 
hills, even to a great height. Sometimes the shells are so nu- 
merous that they foAi, of themselves, the entire mass of the 
stratum. They are everywhere so completely preserved, that 
even the smallest of them retain their most delicate parts, their 
slenderest processes, and their finest points. They are found in 
elevations above the level of the ocean, and in places to which 
the sea could not now be conveyed by any existing causes. They 
are not only enveloped in loose sands, but are incrusted by the 
hardest stones, which they penetrate in all directions." Every 
part of the world, the continents, as well as all the islands of any 
considerable extent, exhibits the same phenomena; these animals 
have, therefore, lived in the sea, and the sea consequently must 



Zbb THE WORLD. 

have existed in the places where it has left them. Indeed,t ne 
proofs of elevation and subsidence, are everywhere too palpable to 
be mistaken. Stratified rocks, or rocks deposited by the agency 
of water, form the summits of the highest mountains, elevated 
many thousands of feet above the level of the sea. In these 
strata, the remains of shells, fishes, and other marine animals are 
imbedded. When in addition to this, we observe these strata 
not horizontal, but nearly vertical, we cannot resist the conclusion 
that they have either been violently upheaved by some tremen- 
dous convulsion, or gradually raised by the irresistable agency 
of a long continued subterranean force. The evidence of dis- 
turbance of the strata, afforded by certain marine worms is im- 
portant, and is an instance of the subservience of the actions of 
even the meanest of created beings, to the elucidation of truth. 
It is well known that certain of these worms, inhabiting straight 
and tubular shells, bore the sand in a vertical direction, as repre- 
sented in this figure, and if the strata remained undisturbed the 




direction of the bore would be always vertical. But the shells 
are found in various strata, making various angles with the hori- 
zon according to the elevation of the strata, as shown in the fig- 
ure below, and occasionally, a more recent*lhell will have the 




vertical direction as at a, boring the cavity subsequently to the 
elevation of the strata. Beds of pebbles, once deposited in reg- 
• ular horizontal strata, are found making angles with the horizon, 
thus witnessing the same fact. 

We will now briefly consider some of the most remarkable 
earthquakes which have occurred within the historic period. We 
commence with the well known one which nearly destroyed th* 



EARTHQUAKE 15 CALABRIA, 1753. 567 

city of Messina in 1763. The shocks commenced on the 6th of 
February, and ended March 28th, though repeated at intervals for 
a space of four year?. The full and interesting accounts of this 
convulsion, carefully prepared by scientific men, render this earth- 
quake of much more importance to the geologist than many others 
which have occasioned infinitely more destruction of life and 
property, but of whose effect in changing the country we are al- 
most entirely ignorant. The concussion of this earthquake was 
felt over a great part of Sicily, and the whole of Calabria, ex- 
tending as far as Naples. The centre of the surface which suf- 
fered the most, was the small town of Oppido, in the neighbor- 
hood of Atramonte, a high, snow-capped peak of the Appenines. 
From this point, for a distance of twenty-fire miles in all direct- 
ions, nearly all the towns and villages were destroyed, and if we 
describe a circle with the same centre, having a radius of seventy- 
two miles, it will include all the country affected by this earth- 
quake. The first shock, February 5th, threw down in the course 
of two minutes, the greatest part of the houses in all the cities, 
towns, and villages, from the western acclivities of the Appe- 
nines, (which traverse Calabria from north to south) in upper 
Calabria, to Messina in Sicily, convulsing the whole country. 
The granitic chain of mountains was slightly affected by the first 
shock, but more sensibly by those that followed ; the principal 
shock being propagated with a wave like motion through the 
tertian* sands, sandstones, and clays, from west to east; and where 
the line of tertiary rocks joined the granite, the shocks were most 
severe, probably owing to the interruption of the undulatory 
movements of the softer strata by the harder granite, whicn pre- 
vented the passage of the shocks to the countries on the opposite 
sides of the mountain range. About 200 towns and villages were 
destroyed, more than one hundred hills slid down, fell together 
and damming up rivers, formed lakes. The quay at Messina 
sank down fourteen inches below the level of the sea. Deep fis- 
sures were caused at several places, and many subsidences, and 
upraisings of the ground took place, and the general features of 
the countn* were so altered that they could scarcely be recognized. 
Thus in a very short space of time the whole country was a« 



268 THE WORLD. 

much changed as though it had been exposed to common influ- 
ences a thousand years, and over 100,000 persons were destroyed. 
The movement of the ground was not only horizontal, but vor- 
ticose, at some places. This was shown by the partial turning of 
the stones of two obelisks at the convent of St. Bruno, in the 
small town called Stefano del Bosco, as exhibited in the wood cut 
below. The position of the stones was changed nine inches 
without their falling. 



The most destructive and tremendous earthquake on record, is 
that which overthrew Lisbon in 1775. The first shock was on 
the morning of November 1st, about half past nine, when, with- 
out any other warning than a noise like thunder, heard under- 
ground, the foundations of this ill-fated city were violently sha- 
ken, and many of the principal edifices fell to the ground in an 
instant. Then with scarcely a perceptible pause, the rumbling 
noise changed into a quick rattling sound, resembling that of a 
wagon driven violently over the stones, this shock threw down 
every house, church, convent, and public building; overwhelm- 
ing the miserable population with the ruins; it continued about 
six minutes. It is said by those who witnessed the effects of this 
earthquake, that the bed of the river Tagus appeared dry in 
many places, and boats sailing on the river were struck violently 



EARTHQUAKE IN PERU, 1746. 269 

as though they had run agrounp!. Perhaps the most extraordinary 
circumstance which occurred during this earthquake was the sub- 
sidence of the new quay called Cats de Prada, built entirely of 
marble, and at an immense expense. A great concourse of peo- 
ple had fled to this quay, as a spot where they might be safe from 
the falling ruins, when suddenly it sank down, with all the peo- 
ple on it, and not one of the bodies ever rose to the surface, and a 
great number of boats, and small vessels, anchored at the quay 
were swallowed up with it, as in a whirlpool, no fragments of 
them ever appeared, and the water at the place of the quay has 
now a depth of upwards of 100 fathoms. At the time of the 
subsidence of the quay, the bar was seen dry from shore to shore, 
then suddenly the sea came rolling in, in a wave about fifty feet 
high. x\bout noon there was another shock, when the walls of 
several houses, which the preceding shocks had not overthrown, 
were seen to suddenly gape open, and then to close again so ex- 
actly that no fissure or joint could be perceived. The extent of 
country afTected by this earthquake is almost incredible. The 
movement was most violent in Spain, Portugal, and the north of 
Africa, but slighter shocks were felt from Greenland and Iceland, 
to Norway, Sweden, Germany, Britain, Switzerland, France, 
Morocco, Fez, and even in the West Indies; and on Lake Onta- 
rio in America. The rate at which the undulatory movement 
was propagated was about twenty miles a minute, judging from 
the interval of time when the shock was first felt at Lisbon and 
the time of its occurrence at other distant places. 

In the year 1746, an earthquake occurred which overthrew Li- 
ma, in Peru, and inundated its port of Callao, so that only 200 
out of 4000 persons escaped. Terrible as were these earthquakes 
yet they seem to have been inferior to some which have occurred 
at a more early date, in many parts of Asia. Earthquakes are 
by no means of uncommon occurrence, scarcely a year passes 
without several. They are now observed with great attention by 
philosphers, and are of the utmost importance in a geological 
point of view. Awful as it must appear to see the ground heav- 
ing and swelling like the troubled sea, hills tottering, and solid 
walls and towns tumbling into ruins, and the earth gaping Qpen» 



§70 THE WORLD, 

suddenly swallowing thousands of terrified men, women, and 
children, yet the philosopher looks beyond this sight of human 
suffering; forgetting the momentary pain and terror, he sees here 
the origin of many of those mighty changes which he had before 
detected, and learns many new facts in regard to the former physic 
cal structure and condition of our planet. We have now con- 
sidered somewhat at length the aqueous, and igneous, causes of 
change in the inorganic world, and we proceed to consider tbe 
agency of the atmosphere and of vital action, 



ATMOSPHERIC CAUSES OF CHANGE. 271 



CHAPTER IX. 

Atmospheric Causes of Change. 

" The seas have changed their beds — the eternal hills 
Have stooped with age — the solid continents 
Have left their banks — and man's imperial works — 
The toil, pride, strength of kingdoms, which had flung 
Their haughty honors in the face of heaven, 
As if immortal — have been swept away." 

Henry Ware. 

We have before described the atmosphere as an elastic fluid 
encompassing the earth, and capable of absorbing large quanti- 
ties of moisture, and have illustrated the formation of clouds and 
the origin of winds. We can easily perceive that so important 
an ti gent may be capable of effecting the most marked changes, 
and we do not now allude to those effects produced by a secon- 
dary agency. Thus, the moisture deposited from the air in the 
form of rain, or snow, upon lofty mountains, causes deluges of 
water to descend and overflow the plains below, or becomes the 
source of those mighty rivers which roll through thousands of 
miles, bearing their immense deposits down to the ocean's bed. 
Changes like these we have already considered, and do not there- 
fore include them in our present description. The atmosphere 
acts as an agent in destroying rocks and changing the face of a 
country, mechanically and chemically. The formation of im- 
mense dunes, or downs, which are heaps of blown sand, is an 
illustration of the former action, and the disintegration and de- 
struction of rocks by the absorption of oxygen, and carbonic acid, 
is an example of the latter ; both of these actions we will now 
briefly consider. . 

The fine sands of the African desert for a long series of ages, 
have been blown by the westerly winds over all the lands capa- 
ble of tillage on the western banks of the Nile, involving in the 



272 THE WORLD. 

almost impalpable powder, ancient cities and works of art, ex- 
cept at a few places sheltered by the mountains. From the fact 
that these moving sands have only reached the fertile plains of 
the Nile in modern times, it was inferred by M. de Luc, that that 
continent was of recent origin. The same scourge he observes, 
would have afflicted Egypt for ages anterior to the time of histo- 
ry, had the continents risen above the level of the sea several 
hundred centuries before our era. But as Mr. Lyell very justly 
observes, there is no evidence that the whole African continent 
was raised at once, and it is possible Egypt and the neighboring 
countries might have been populated long before any sands began 
to be blown from the western portion, nor is there yet any evi- 
dence of the depth of this drift sand, in the various parts of the 
great Lybian deserts. Valleys of large dimensions may have 
been filled up, and may thus have arrested the progress of the 
sand drift for ages. The sand floods which have buried the works 
of art on the western countries of the Nile, have contributed 
greatly to their preservation. Nothing could be better adapted 
than this dry impalpable dust, to protect the features of the col- 
lossal sculptures of the temples, or the paintings upon their walls. 
Every mark of the chisel remains as perfect as though but yes- 
terday from the sculptor's hand, and the colors of the paintings 
are as brilliant, as when first laid on, thousands of years ago. At 
some remote period, when the causes that now make the air 
move in sweeping winds across the Great Desert towards the 
Nile shall be removed, when the change of land and sea will 
perhaps open that desert to the ocean, after the pyramids shall 
have crumbled, towns and temples of higher antiquity, will be 
laid open, and a flood of light be shed upon the history of remote 
ages. Ere that time, the hieroglyphic writing will be thoroughly 
understood, and the years of the Egyptian dynasties as well de- 
termined as the reigns of modern kings. The great agent of de- 
composition in other places, moisture, is unknown there. The 
spectator who looks for the first time upon the immense cavern 
temple at Ipsambul in Nubia, might well imagine that the artists 
had just left their work. The walls are as white, the colors as 
perfect, and the outlines as sharp, as in the first hour of their ex- 



sand Floods. 273 

istence, and when he surveys the tracings, and half-finished 
sculpture he might almost look for the return of the artists to 
complete their work. Such is the wonderful preservation of 
these works in the fine blown sand of the great deserts* that al- 
though the buildings have been roofless for two thousand years, 
the paintings are undefaced. '* There are some small chambers 
in a temple at Abydos" says Sir F. Hennicker, "in which the 
color of the painting is so well preserved that doubts immediate- 
ly arise as to the length of time that it has been done. The best 
works even of the Venetian school, betray their age; but the col- 
ors here, which we are told were in existence two thousand years 
before the time of Titian, are at this moment as fresh as if 
they had not been laid on an hour." The preservation of works 
usually esteemed as fugitive, being so perfect, we might expect 
that those executed in more durable materials the sienite, granite, 
basalt, and limestone, would be still more so, and we find frag- 
ments of temples leveled to the ground by Cambyses, five hun- 
dred years before the Christian Era still retaining their pristine 
polish. The north and east faces of the obelisk, still erect among 
the ruins of Alexandria, retain much of their original sharpness, 
but the south and west sides have been entirely -defaced by the 
attrition of the minute particles of sand with which the air is 
charged, beating against them sixteen hundred years. The des- 
olation brought upon those ancient cities by the irresistable en- 
croachments of the desert, the remains of its immense temples 
and works of art, its silent chambers, where the wrapped-up dead 
have remained for two hundred centuries, who once trode the 
streets of ancient Thebes, with all the buoyancy of feeling and 
all the hope which animates men now, furnishes a striking in- 
stance of the influence of apparently insignificant causes, in pro- 
ducing the greatest results, and remind us of the prophet's decla- 
ration, " Wo to the land shadowing with wings." But the an- 
cient cities of Nubia, and Upper Egypt, are not the only places 
buried in blown sand, there, are numerous instances of towns 
and villages, in England and France, thus overwhelmed. For 
example, near St. Pol de Leon, in Brittany, a whole village was 
completely buried beneath drift sand, so that nothing but the 



274 t«E WORLD. 

spire of the church could be seen. In the course of a century it 
is said that a thousand acres of land in Suffolk were covered by 
blown sand; and a considerable tract of land on the north coast of 
Cornwall has been thus inundated, and ancient buildings are of- 
ten brought to light by its shifting; and in some cases, in boring 
for water, distinct strata of the sand separated by a vegetable 
crust are found. The name of dunes, or downs, has been given 
to these moving sand hills, which are first generated on the sea 
shore. The sea-breeze drives the fine sand, farther and farther 
inward, until it accumulates and becomes a formidable hill. 
There are many instances of these hills in the United States* 
particularly in the south eastern part of Massachusetts, and near 
Cape Cod, where they are sixty or seventy feet high, and of al- 
most snowy whiteness. Here these dunes are moving gradually 
westward, the strength of the land-breeze not being sufficient to 
counteract the effect of the sea-breeze. A series of these dunes 
now threaten the village and Bay of Provincetown, and large 
quantities of beach-grass have been transplanted to their ridges 
for the purpose of arresting their progress. 

The chemical agency of the atmosphere is another important 
means of change producing a sure and often rapid decay of the 
solid materials of our globe. The forces of chemical affinity are 
superior to those of cohesion and aggregation, and the atmos- 
phere charged with moisture ancf carbonic acid gas, disintegrates 
the solid materials, which crumble, away before this •« gnawing 
tooth of time." The resistance which rocks afford to decom- 
position depends greatly upon their composition, but all are more 
or less affected. A very slight examination of the soil in any 
rocky country will suffice (o show that it has been derived from 
the decomposition of the rocks in the vicinity. In granitic coun- 
tries we find the soil made up of shining particles of silex or 
quartz, and spangles of mica, and particles of felspar, and even 
the finest portions will be found thus composed. Sienite and 
hornblend rock, when decomposed, yield a darker soil, containing 
much more felspar and less quartz, while slaty rocks give a dark 
colored tint to the soil, forming beds of tough blue clay, when 
deposited by water. We have already alluded to the consolida- 



CHEMICAL INFLUENCE OF THE ATMOSPHERE. '21b 

lion of loose materials by the infiltration of calcareous matter, or 
' by iron ; the destruction of such aggregations is no less remark- 9 
able. Thus we find rocks which contain iron pyrites or sulpur- 
et of iroiij constantly crumbling to pieces. The oxygen of the 
atmosphere, and of the watery vapor with which it is charged, 
combining with the sulphur, forms sulphate of iron or copperas, 
the sulphuric acid of which, acts powerfully on the rock. Rocks 
which contain potash and soda are also very liable to disintegra- 
tion. • Indeed, it is not a little remarkable that our supplies of 
these valuable alkalies, particularly of the potash, are obtained 
from the vegetable kingdom, salts of potash containing some 
vegetable acid are of constant occurrence in plants, performing a 
hidden but yet important part in their economy ; when these 
plants are burned, the organic acids are destroyed, and the potash 
remains in the state of carbonate, or united with carbonic acid* 
The great natural depository of potash is the felspar of the gran- 
itic and other unstratified rocks, combined with silica in an in- 
soluble state. When these rocks disintegrate into soil, the alkali 
acquires solubility. Rocks which readily absorb moisture are 
liable to decay ; the red sandstone, or freestone, for example* 
which is destroyed very rapidly according to its porosity, by the 
splitting of portions of the stone in consequence of the freezing 
of the water. De la Beche, observes that, " rocks receive con- 
siderable chemical modification by the percolation of water 
through them. There is scarcely any spring-water, which does 
not contain some mineral substances in solution, which it must 
have procured in its passage through the rocks. Now, though 
this quantity may be small, when we regard the composition of 
any particular spring-water, yet, when we consider the soluble 
matter contained in the spring-waters of any given 1000 square 
miles of country, and that this subtraction of matter from rocks 
has been going on for ages, we may readily conceive that the 
chemical change, may be greater than, at first sight we might 
anticipate. We may also infer that the most soluble portions of 
rock, have a constant tendency to be removed, when exposed not 
only to direct atmospheric influences, but also to the percolation 
of rain-water through them, so that most rocks would experience 



S76 tftE WOULD. 

great difficulty in resisting chemical changes of this kind, and of 
preserving their original chemical nature, more particularly when 
elevated into the atmosphere*" We have already had occasion 
to remark upon the large amount of calcareous and silicious mat- 
ters held in solution by water, which matter has been often de- 
rived from the percolation of that fluid through limestone districts, 
or rocks containing felspar, for it is well known that in the de- 
composition of such rocks, producing the porcelain clay, an 
enomous quantity of silex is carried off in solution. In the re- 
gion of extinct volcanoes in France, the district of Auvergne, 
the destruction of granite is very rapid, owing to the liberation 
of large quantities of carbonic acid. "The disintegration of 
granite," says Lyell, " is a striking feature of large districts in 
Auvergne. This decay was called by Dolomieu 'la maladie du 
granite,' and the rock may, with propriety, be said to have the 
rot, for it crumbles to pieces in the hand. The phenomenon may, 
without doubt, be ascribed to the continual disengagement of 
carbonic acid gas from numerous fissures. In the Plains of the 
Po, I observed great beds of alluvium, consisting of primary peb- 
bles, percolated by spring water, charged with carbonate of lime 
and carbonic acid in great abundance. They are, for the most 
part, incrusted with calc sinter ; and the rounded blocks of gneiss, 
which have all the outward appearance of solidity, have been so 
disintegrated by the carbonic acid as readily to fall to pieces." 

We can now perceive how little of stability or permanancy is 
inscribed upon the face of nature. The gilded insect which flut- 
ters its short hour over the flowers of a day, deems its life and 
happiness lasting, and what better are our own thoughts; we look 
upon the earth as unchangeable, when, for ought we know, the 
next instant may behold all our possessions swallowed up, or blown 
into the air. We carve to ourselves costly monuments, perpetua- 
ting the deeds of martial bravery, or the fame of a patriot, wo 
protect them from the hands of the rude by various means, but 
a more formidable enemy, because less known, and dreaded, is 
passing by, and silently effecting the work of desolation. Change, 
perpetual change, is inscribed by the finger of the Almighty up- 
on the face of everything. No art can arrest the insidious at- 



DESTRUCTION OF ROCKS. 



277 



tacks which thus cause the richest works of man to crumble si- 
lently away. 

•* It is painful," says Philips, " to mark the injuries effected by 
a few centuries on the richly sculptured arches of the Romans, 
the graceful mouldings of the early English architects, and the 
rich foliage of the decorated and later Gothic styles. The chang- 
ing temperature and moisture of the air communicated to the 
slowly conducting stone, especially on the western and southern 
fronts of buildings, bursts the parts near the surface into powder, 
or, by introducing a new arrangement of the particles, separatee 
the external from the internal parts, and causes the exfoliation or 
desquamation, as Mac Culloch caljs it, of whole sheets of stone 
parallel to the ornamental work of the mason. From these at- 
tacks no shelter can wholly protect; the parts of a building which 
are below a ledge often decay the first; oiling and painting will 
only retard the destruction; and stones which resist all watery 
agency, and refuse to burst with changes of temperature, are 
secretly eaten away by the chemical forces of carbonic acid and 
other atmospheric influences. What is thought to be more dura- 
ble than granite ? Yet this rock is rapidly consumed by the 
decomposition of its felspar, effected by carbonic acid gas; a pro- 
cess which is sometimes conspicuous even in Britain, but is usu- 
ally performed in Auvergne, where carbonic acid gas issues plen- 
tifully from the volcanic regions." 

The most durable rocks appear to be the limestones of the 
Silurian formation, but some of the sandstones of the more re- 
cent formations are exceedingly perishable. This may be seen 
upon examining the tombstones of red sandstone, which were 
formerly used very extensively in New England, their inscriptions 
will generally be found illegible. The durability of sandstones 
depends much upon the nature of the cement which binds the 
particles together, if this be calcareous they are not so durable as 
if silicious, and if the stones contain iron, they are generally 
highly perishable. Such stones wkich, may always be detected 
from their iron-brown, or rusty appearance, should be rejected 
for building stone. 



^78 THE WOKLD, 

Such are some of the effects of causes continually, and yet 
silently operating around us. It is true that many years are re- 
quired to produce changes of great importance, and the opera- 
tion is so gradual that the wonder ceases, almost ere it begins 
In investigations however, so comprehensive as those we have 
been considering, a day, a year, or a hundred years, is but as the 
grain of sand to a mountain. It is indeed very true that the pres- 
ent generation may pass away, and yet think they leave all things 
as they were of old, looking with a listless apathy upon the face of 
nature. The true philosopher improves the fleeing moment, and 
enlarges his affections, and expands his imagination by the con- 
templation of loftier subjects, and so fits himself to depart from 
this changing scene, with the consolation of not having lived in 
vain. 



ViTAf. CAUSES or CHANGE. 2f9 



CHAPTER X, 

Coral Animalcules. 

s * Deep in the wave is a coral grove, 

Where the purple mallet and gold-fish rove, 
Where the sea-flower spreads its leaves of blue, 
That never are wet with falling dew, 
But in bright and changeful beauty shine, 
Far down in the green and glassy brine." 

PercivaL 

We now enter upon a most interesting branch of our subject, 
the influence of organic action in producing change, and we will 
soon find that of-all agents which at the present moment are form- 
ing rocks, the most remarkable are those minute and fragile ani- 
mals termed Coral Animalcules. A vast number of islands in 
the Pacific, Indian, and Atlantic oceans are entirely composed of 
the calcareous skeletons of these minute animals, and they are at 
the present moment rapidly increasing in their extent. Straits 
and seas, once easily and safely navigable, are now rendered ex- 
tremely dangerous, and even impassable. It will not be unpro- 
fitable or uninteresting to devote a short space to the considera- 
tion of these wonderful specimens of organic existence. 

The nature of coral animalcules is but little understood by most 
persons, they suppose that the hard calcareous substance called 
coral, is a part of the animal itself, this, however, is not the case. 
The stony substance, may be compared to an internal skeleton, 
for it is surrounded by a soft animal investment, capable of ex- 
panding, and when alarmed, of contracting and drawing itself 
almost wholly into the hollows of the hard coral. Though often 
beautifully colored in their own element, yet when taken out of 
the water they appear like a brown slime spread over the stony 
nucleus. The coral animalcules exist in e great variety of form • 



280 



TKE WOKLD. 



and of various sizes, some of them are so minute that they cannot 
be seen without a microscope. They are congregated together 
like other zoophytes, each individual being connected to a com- 
mon body, so that what is received by any one goes to the nour- 
ishment of the whole. The stony matter, or hardvsubstance of 
the zoophyte, is formed as are the bones and nails in man, by se- 
cretions from the animal substance, by which they are penetrated 
and invested. The cells of the coral, therefore are not built up 
by the polypi, as they are called, in the same manner as the wax- 
en cells of the bee. We may often observe little patches of 
yellowish calcareous matter on sea- weed, or shells thrown upon 
the shore, this upon examination appears to be a kind of delicate 
net-work, but when examined with a microscope the substance is 
found to be full of pores, and if the examination is made while 
the flustra or calcareous matter is immersed in the water, each 
pore will appear to be the opening of a cell, whence issues a tube 
with several long arms or feelers; sometimes these expand, and 
then suddenly close and are withdrawn into the cells, then issue 
forth again. Thus each individual of the group occupies its own 
particular cell, but the whole constitutes one family of polypes 
connected by a common integument, or fleshy or gelatinous sub- 
stance which invests the whole. Figure 1, of the wood-cut be- 
low exhibits the series of cells of the flustra, systematically 




'W 



arranged. Each cavity is the receptacle of a polype shown with 
the tenlacula, or feelers, expanded in fig. 2, and contracted into 
its cell in fig. 3. These views are from drawings made by Mr. 
Lister, and figured by Dr. Mantell, in his excellent " Wonders of 
Geology. " The animals just described are members of the same 



BRA IN -STONE CORAL. 



281 



family by whose secretions vast reefs of coral rocks are formed, 
and mountain masses of calcareous matter produced. They be- 
long to the order Coraliferi, or coral-making, and the class 
Polypi of Cuvier's Animal Kingdom. The mode of increase of 
the polyparia is very remarkable. If the flustra just referred to, 
be carefully watched, a small globule will be observed to be thrown 
off from the mass, and attaching itself to the sea-weed or rocks, 
.will become the germ of a new colony of this compound animal, 
as it increases in size it will exhibit upon closer inspection the 
usual characteristics of the flustra, and if the gelatinous or jolly- 
like substance is removed, a small spot of calcareous matter will 
be found. The stony secretions of the coral forming animals, 
appears upon examination to be of the same character as that of 
shells; some specimens appearing of the same composition as 
the pearly shells, and others the same as the enamelled shells. In 
form and color there is condiderable diversity. Our limits will 
only permit us to give figures of several of the different species, 
without a lengthened or minute description. The most common 
varieties of corals, which compose the coral reefs and banks, are 
the following, according to Lamarck. The Meandrina, or brain- 
stone coral, which derives its name from the meandering cells, 
and its general appearance, which resembles the brain, as figured 
below. Figure, 1, represents the animal as seen alive in the sea, 





the polypi are retracted or concealed, it is of a reddish or fawn 
color. Fig. 2 is the coral as it appears when divested of its gelatin- 
ous covering. This zoophyte sometimes attains the size of four 
feet in circumference. The base of the Meandrina is firmly at- 
tached to the rocks with which it soon becomes identical : as each 



282 



THE WORLD. 



successive fleshy mass expires, a new one appears, which gradu- 
ally expands and deposits its calcareous secretions upon the old 
one, and thus vast beds of stony matter are accumulated in the 
bottom of the sea, and become the foundations of coral reefs and 
islands. "We may compare" observes Mr. Lyell, "the opera^ 
tion of these zoophytes in the ocean to the effects produced on a 
smaller scale upon the land by the plants which generate peat, 
In the case of the Spagnum, (page 204), the upper part vege- 
tates while the lower portion is entering into a mineral mass, in 
which the traces of organization remain, when life has entirely 
ceased. In corals, in like manner, the more durable mate- 
rials of the generation that has passed away, serve as the founda-* 
tion on which living animals are continuing to rear a similar 
structure." The Caryophilla, or branched star-like coral, is an- 
other common species. We give an engraving of an American 
specimen as it appears when alive. The three branches, each 




contain a bright green polypus. The Astrea, is another very 
common and extensive species of coral, fig. 1, represents the 



*Mt* 




coral as seen alive in the sea, the polypi are of a dark green 



MADREPORES. 283 

color, and about half an inch in length, protected by deep lami- 
nated polygonal cells one-sixth of an inch wide; fig. 3, represents 
the coral with the animal removed, its name astrea or star-like, 
is derived from its radiated or starry appearance. Fig. 2, is a 
magnified view of one of the polypes. The tentaculae, or arms, 
are seen arranged around the mouth. The appearance of these 
animals alive, and in activity, is most beautiful when viewed in 
tranquil water. The surface of the rock appears like a living 
mass, presenting a great diversity of appearance and color. The 
Madrepore, or branched cellular coral, is well known, being per- 
haps the most common species. It will be immediately recog- 
nized upon inspecting the figure we have given below. In some 




species after the fleshy investment perishes, the little cells appear 
very numerous as in the figure. The white branched corals usu- 
ally seen in collections belong to this genus. In the water, the 
Madrepores are invested with fleshy integuments of various colors 
and each cell is furnished with its own polype. We have now 
enumerated the several species of zoophytes most active in the 
formations of reefs. The stony secretions of all these, when 
bleached by the action of moisture and light, are of a dazzling 
whiteness. There is however, a species of coral, Corallium ru- 
brum, or red coral, the stony secretion of which is a bright red 
color, very beautiful and susceptible of a high polish. A speci- 
men of this coral is here figured. It consists of a brilliant red 
stony axis invested with a fleshy or gelatinous substance of a pale 



£84 THE WORLI*. 

blue color, attached to the rocks by a broad expansion of its base. 




In the figure, the fleshy substance is removed at the extremities 
to exhibit the stony axis. It is seldom found more than a foot in 
length, and is well known, being used for various ornamental 
purposes, and is obtained by dredging in various parts of the 
Mediterranean and Eastern seas. Another species of red coral* 




the organ-pipe, or tubipora, is shown in the above wood-cut*, 
this derives its name from its tubular appearance, being com- 
posed of parallel tubes united by lateral plates or transverse- 
partitions placed at regular distances. The polypi of this coral are 
of a beautiful green color. This species occurs on the coast of 
New South Wales, and in the islands of the Molucca group, in 
hemispherical masses of from one to two feet in circumference* 
which first appear as small specks, adhering to the rock, these 
gradually increase, and. the tubes shoot forth like little rays; other 
tubes spring from the transverse plates, finally constituting a uni- 
form tubular mass, the surface being covered with a green fleshy 
substance, beset with stellar animalcules. 

The geographical distribution of corals is very extended. The 
Pacific, throughout a space comprehended between the 30th' 
parallel of latitude on each side of the equator is very productive, 
and also the Persian and Arabian Gulfs. They are very abundant 



APPEARANCE OF LIVING CORALS. 285 

in the Indian ocean and some parts of the Atlantic. Many spe- 
cies of this genus are found along our Atlantic coast and on the 
shores of England. Some species seem to prefer the more ex- 
posed situations, flourishing in the greatest profusion, on rocks 
and plants which the tide every day leaves bare ; the larger 
polyparia however, are seldom found in places exposed to violent 
currents; they flourish in the submarine grottoes and hollows of 
the rock, where they shoot out their delicately branching forms 
studded with zoophytes of most brilliant colors. Others attach 
themselves to the flexible branches of the sea plants, encasing 
them in a living tomb, and are thus fitted to enjoy the powerful 
action of the surges; the pliant branches bending to and fro, with 
the movements of the waters. Others form immoveable rocks, 
and slowly increase, until at last an island is elevated above the 
waters. The distribution of corals, like that of plants, varies with 
the climate. In the colder northern latitudes, a few sponges, and 
sertulariae alone are found, but in the warmer, equatorial regions, 
within the tropics, they attain a luxuriance and beauty, a gran- 
deur and importance well worthy our attention. Here, in an 
ocean of uniform temperature, they elevate those immense reefs 
which eventually become the habitations of men, and even gar- 
dens producing rich tropical fruits and flowers. These minute 
beings, myriads upon myriads, here exercise their empire, some- 
times, in the sheltered places, or still lagoons, shooting forth the. 
most delicate branches, and in others, wheL*e the surges beat upon 
them, growing firm and solid as the rock on which they are based . 
The appearance of the living corals in the water is described as 
most enchanting. The whole bed of the Rod Sea is absolutely 
a forest of sea-plants and corals, presenting the appearance of a 
submarine garden of the most exquisite verdure, resembling in 
splendor and gorgeous coloring the most celebrated parterres of 
the East. Ehrenberg, the distinguished German naturalist, so 
well known by his admirable investigations of infusorise, was so 
struck with the view of the living corals in the Red Sea, that he 
exclaimed with enthusiasm •■ Where is the paradise of flowers 
that can rival in beauty these living wonders of the ocean ?" Some 



286 THE WORLD. 

have compared their appearance to beds of tulips or dahlias; and, 
in truth, the large fungi se, with their crimson disks, and purple 
and yellow tentacula, bear no slight resemblance to the latter. 

The tender branches of the corals furnish food to some species 
of fish, which graze upon them in whole shoals, both within the 
lagoons in the quiet waters, and among the breakers on the out- 
side of the reef. Nothing can be imagined more beautiful than 
the scene presented in the tropical climates, especially where the 
shore consists of alternate beds of sand, and masses of rock. 
" Groves of coral are seen expanding their variously colored 
clumps, some rigid and immovable, and others waving grace- 
fully their flexile branches ; shells of every form and hue, glide 
slowly among the stones, or cling to the coral boughs like fruit ; 
crabs and other marine animals, pursue their prey in the cran- 
nies of the rock, and sea-plants spread their limber fronds, in 
gay and guady irregularity, while the most beautiful fishes are on 
every side sporting around." 



FITAE CAUSES OF CHANGE. 287 



CHAPTER XI. 

Coral Islands. 

** I saw the living pile ascend, 
The mausoleum of its architects, 
Still dying upwards as their labors closed ; 
Slime the materials, but the slime was turned 
To adamant by their petrific touch." 

J. Montgomery. 

Having in the preceding chapter given a brief description of 
some of the more common varieties of corals, we shall now con- 
sider more fully the agency of these wonderful anima:s in the 
formation of rocks. It has been generally considered that the 
zoophytes cannot live in water of very great depths, and that 
therefore their structures are based upon submarine mountains. 
This view has been confirmed by the observations of Ehrenberg, 
and more recently by the careful soundings of Captain Fitz Roy, . 
of the Royal English Navy. At a depth of ten fal horns the pre- 
pared tallow invariably came up marked with the impressions of 
the living corals, and as clean as if it had been dropped on a car- 
pet of turf ; at a greater depth the impressions were less numer- 
ous, and the adhering particles of sand much more frequent, 
until at a mean depth of twenty-five fathoms it was evident that 
the bottom consisted of a smooth sandy layer. We may conclude 
therefore that the reef building corals, do not usually flourish 
much below this depth. The formation of the coral islets is 
somewhat analagous to the growth of a tree which has been 
headed. The zoophyte cannot endure even a short exposure to 
the sun's rays in the air, their growth upv ards is therefore checked 
as soon as the surface of the water is reached. They spread out 
laterally however, not unlike the top of a tree. 

The appearance and formation of coral islands has been de- 
scribed very minutely by a great number of distinguished natural- 



288 THE WOflL©. 

Jsts, and various theories have been proposed to explain the ob- 
served phenomena. We have devoted some little attention to 
this part of our subject, and are best satisfied with the explanation 
given by Mr. Chas. Darwin, in a paper read before the Geologi- 
cal Society in May 1837, and which we will explain presently- 
Everywhere in the Pacific and Indian Oceans, within the tropics, 
may be seen coral banks in their various stages of progress ; som* 
covered with light soil, and the habitations of man. Most of the 
reefs which raise themselves above the waters are of a circular 
form, enclosing a basin of still water, called a lagoon f which, 
connects by means of one or two channels with the sea. In the 
interior of the island, the more delicate and smaller kinds of 
zoophytes live, while the stronger and hardier species, fitted to 
endure the beating of the surf, flourish on the outer margin of 
the isle. When the reef rises so high that it is left uncovered at 
low water, the corals cease to increase, the animals die, and the 
branches become somewhat decomposed. Fragments of coral 
limestone are thrown up by Ihe waves, with shells, and broken 
fragments of crustacean animals, seeds are floated by the waves 
towards the new formed island, and thrown upon its shores ; and 
trunks of trees, drifted thousands of miles, find a lodgment upon 
it, bringing with them small animals, as insects and lizards. 
Bushes and trees, spring up, and the sea-birds nestle there, and 
finally at a later period, it becomes the habitation of man. The 
reefs of coral, consist not only of the corals, and their broken 
fragments, but masses of comract limestone, and imbedded shells 
are of frequent occurrence. The limestone is found sometimes 
in the uppermost or newest parts of the reef, and is formed by 
chemical decomposition, the carbonate of lime being supplied 
from the decomposition of corals and testacea. 

We have already alluded to the geographical distribution of 
corals, we may however, form some idea of the immense extent 
of the coral reefs when we learn that, off the coast of Malabar, 
in the Indian Ocean, there is a chain of coral islands of over 480 
miles in length, called the Maldiva Group. On the coast of New 
Holland, is an unbroken reef 350 miles in length, and between 
that and the island of New Guinea is a coral formation which 



ATOLLS. 283 

extends upwards of 700 miles ; and Disappointment Island and 
Duff's Group, are connected by a coral reef of 600 miles length, 
over which the natives pass from one island to another. 

Coral reefs are divided into three great classes, namely Atolls, 
Barrier, and Fringing reefs. The word atoll is the name given 
by the natives to the circular islands enclosing a lagoon, or still 
water in the centre. This is the most usual form of the coral 
islands, and fails not to strike the attention of every one who has 
crossed the Pacific. They occur of all sizes ; of thirty-two ex-? 
aniined by Capt. Beechy, the largest was thirty miles in diameter, 
and the smallest less than a mile, they were of various shapes 
and all but one, formed by living corals. This one had been 
raised from the water about eighty feet, but was of coral forma- 
tion, and was encircled by a reef of living corals. All were slowly 
increasing their size, and twenty-nine of them had lagoons in the 
centre, which had probably existed in the others, until, in the 
course of time, they were filled by the labors of the zoophytes, 
and other substances. It was supposed by the earlier voyagers 
that the coral-building animals instinctively built in the form of 
great circles to protect themselves from the fury of the waters. 
So far however, from this being the case, we have seen that those 
massive kinds upon whose existence and increase, the reef de- 
pends, flourish best among the breakers on the outside of the 
reef. Another and more probable theory, is that advocated by 
Mr. Lyell, that they are based upon the crests of submarine cra- 
ters, and this idea receives confirmation from the steep angle at 
which tht island plunges at all sides into the surrounding ocean, 
and that every island yet examined in the immense region called 
Eastern Oceanica, consists of volcanic rocks, or coral limestones. 
In opposition to this opinion it is very plausibly argued by Mr. 
Darwin, that the form and size of some, and the number, prox- 
imity, and relative positions of others, are incompatible with this 
theory. Thus, Suadiva atoll is 44 geographical miles in diame-? 
terin one direction, and 34 in another; Rumsky atoll is 54 by 20. 
miles across; Bow atoll is 30 miles long, but only six in width. 
Another theory, proposed by Chamisso, accounts for the circular 
form of coral islands upon the well known fact, that the corals 



290 



THE WORLD. 



growing more vigorously around the outside where exposed to the 
sea, the outer edges would grow up from the foundation before 
any other part; thus making a ring or cup-shaped structure; but 
we are not by this theory relieved from the difficulty of answer- 
ing the question, upon what are these massive structures based ? 
since it is well known that the reef-building corals cannot live at 
any very considerable depth, though indeed, other species have 
been found at a depth of 60 fathoms. Below we give a view of 
one of these islands, copied from Capt. Beechy. The circular 
form is well exhibited in this island, which is called Whitsunday, 
but it gives a faint idea of the singular appearance of an atoll. 




being one of the smallest size. The immensity of the ocean, the 
fury of the breakers, contrasted with the lowness of the land, 
and the smothness of the bright green water within the lagoon 
can hardly be imagined without having been seen. 

The second great class of reefs are the Barrier-reefs, these are 
similar in all respects to the atolls except having a high land like 
a castle rising out of the lagoon. The following sketch from Mr. 
Darwin, will give an idea of the appearance of one of these 
wonderful structures, being a part of the island of Bolabola in 
the Pacific, as seen from one of the central peaks. In this in- 
stance the whole line of reef has been converted into land, upon 
which trees are growing; but generally, a snow-white line of 
breakers, with onlv here nnd there a lowisl^t covered with rocon- 



BARRIER REEFS. 



291 



nut trees, can be seen separating the dark heaving waters of the 
ocean from the light green expanse of the lagoon, the still waters 




of which, within the reef, usually bathe a fringe of low alluvial 
soil, upon which the varied and beautiful productions of the tropi- 
cal regions flourish at the foot of the abrupt and wild central 
peaks. In the sketch given above, the barrier-reef may be seen 
in the distance skirting around the island. These reefs are of all 
sizes from three to forty miles in diameter; and the one winch 
encircles both ends and fronts one side of New Caledonia is up- 
wards of 400 miles long. Externally the reef rises like an atoll 
with abruptness out of the profound depth of the ocean, but in- 
ternally it either slopes gradually into the channel, or terminates 
in a perpendicular wall 200 or 300 feet in height. 

There is one remarkable feature connected with the circular 
reefs, and that is, a deep and narrow passage almost invariably 
opening from the sea into the lagoon, and kept open by the efflux 
of the sea at low tides, and it has long been remarked in the 
case of the barrier reefs, that this channel or opening alway 
faced valleys in the included land. 

The third great class are the Fringing reefs, these, so far as the 
coral reef itself is concerned, do not differ materially from the 
others, except that the encircling belt of coral is much narrower. 
Where the land slopes abruptly into the water the reefs are but a 
few yards in width, forming a mere ribband or fringe around the 
island, but when the slope is gradual, the width is much increased 



292 THE WORLD. 

extending sometimes as far as a mile from the land, and always 
to such a distance from the shore that the limiting depth of 20 or 
30 fathoms is obtained, where the reef ceases. From the more 
flourishing growth of the outermost corals, the fringing reefs are 
usually highest at the outside, and the sediment washed inwards 
upon the reef, generally produces in the course of time, a shallow 
sandy channel. Such are the three great classes of coral reefs 
which are found scattered throughout the vast oceans, and princi- 
pally in the tropical regions, but it must by no means be supposed 
that they are found indiscriminately united, on the contrary the 
atolls and barrier-reefs are never found in proximity to the fring- 
ing reefs. It has been remarked with surprise that while atolls 
are the most common coral structures throughout some vast por- 
tions of the ocean, such as the tropical Pacific and the Indian 
Oceans, they are entirely wanting, or very nearly so, in the tropi- 
cal Atlantic and West Indian Seas, where the corals themselves, 
are exceedingly numerous. There is also another somewhat re- 
markable fact, that no single active volcano occurs within several 
hundred miles of a coral archipelago, or even a small group of 
atolls ; and although most of the islands in the Pacific which are 
encircled by barrier-reefs are of volcanic origin, having remains 
of craters distinctly visible, yet not one of them is known to have 
been in eruption since the growth of the corals. In explaining 
by any theory the formation of coral reefs, we must consider all 
the phenomena presented by the three great classes as enumera- 
ted in the preceding description. To ourselves the explanation 
proposed by Mr. Darwin in his volume upon •« The structure and 
distribution of Coral Reefs," is the most satisfactory, and may be 
briefly stated thus; islands, or a line of coast, being first skirted 
with fringing reefs, become atolls by a continual but gradual subsi- 




LEVEL OF SEA 
dence of the land. Let us then take an island surrounded by 



BARRIER REEFS. 293 

fringing reefs, and let this island with its reef, represented by the 
unbroken lines in the wood cut, slowly subside. As the island sinks 
down, the reel continually grows upward; as the island subsides 
the space between the inner edge of the reef and the beach be- 
comes proportionally broader. A section of the reef and island 
in this state is represented by the dotted lines, A A, being the 
outer edges of the reef; C C, the lagoon; B B, the shores of the 
encircled island. This section is a real one (on the scale of .388 
of an inch to the mile), through Bolabola in the Pacific. We 
can now see why the barrier reefs are so far from the shores which 
they front. Supposing the island to still subside, the corals mean- 
time growing vigorously upward, the last traces of land will finally 
disappear, and a perfect atoll be formed. We thus perceive why 
atolls so much resemble the barrier reefs in general size, form, 
and manner in which they are grouped together, for they are but 
the rude outlines of the sunken islands over which they stand. 
In proof of the foregoing simple and not at all improbable cause 
for the formation of barrier reefs, and atolls, Mr. Darwin gives 
some examples of actual subsidence now in progress, and also 
presents some evidence of the recent elevation of those islands 
and coasts which have fringing reefs. The sinking of the islands, 
or coast, for the formation of barrier reefs, or atolls, must neces- 
sarily have been very slow, and undoubtedly large archipelagos 
and lofty islands 4>nce existed, where now only rings of coral rock 
scarce break the open expanse of the sea; thus the only record 
left to us of the existence of vast tracts of land are the wonderful 
memorials of these busy architects ; in each barrier reef we see 
evidence of land subsided, and in each atoll a monument of an 
island lost. Busy from the first ages of the world, when the 
primeval seas had but a few groups of living beings, of the low- 
est order of organization, the coral polype has toiled from day to 
day, and year to year, and is toiling now. What mighty changes 
have passed over our globe since that remoie period in which ihe 
Geologist is first enabled to trace the existence of living beings 
upon the earth. How many tens of thousands of times the earth 
has revolved around the sun, and how many huge mountain 
chains of granite have been disintegrated, and their scattered frag- 



294 THE WORLD. 

ments deposited in the deep bed of the ocean. Perhaps the 
foundation of some of our present coral islands, was begun in 
those remote ages, and that the successive architects of the solid 
pile, have reared a structure which has witnessed* more than 
one revolution of the major axis of the earth's orbit. 

We close with the following beautiful description of a coral 
grove, by Percival. 

" The floor is of sand, like the mountain-drift, 

And the pearl-shells spangle the flinty snow ; 
From coral rocks the sea-plants lift 

Their boughs, where the tides and billows flow ; 
The water is calm and still below, 

For the winds and the waves are absent there ; 
And the sands are bright as the stars that glow 

In the motionless fields of the upper air. 
There with its waving blade of green, 

The sea-flag streams through the silent water, 
And the crimson leaf of the dulse is seen 

To blush like a banner bathed in slaughter ; 
There with a light and easy motion 

The fan-coral sweeps through the clear deep sea ; 
Aud the yellow and scarlet tufts of ocean 

Are bending like corn on the upland lea ; 
And life in rare and beautiful forms 

Is sporting amid those bowers of stone, 
And is safe when the wrathful spirit of storms 

Has made the top of the waves his own. 
And when the ship from his fury flies 

Where the myriad voices of ocean roan, 
When the wind-god frowns in the murky skies, 

And demons are waiting the wreck on shore, 
Then far below in the peaceful sea 

The purple mullet and gold-fish rove, 
Where the waters murmur tranquilly 

Through the bending twigs of the coral-grove f JJ 



ORGANIC REMAINS. 395 



CHAPTER XII. 

Organic Remains. 

•* And thou didst shine, thou rolling moon, upon 
All this, and cast a wide and tender light, 
Which softened down the hoar austerity 
Of rugged desolation, and fill'd up, 
As 'twere, anew, the gaps of centuries." 

Byron. 

In the preceding chapters we have, though somewhat imper- 
fectly, given a sketch of the great causes of change now in ope- 
ration on our globe, and we have shown that the earth's surface 
has been, and still is, subject to perpetual mutations. What was 
once dry land is now the bed of tie ocean, and what is now 
the bed of the sea will one day be elevated land. We have also 
seen that the crust or superficial covering of the globe is com- 
posed of strata succeeding each other in a well determined and 
regular order, and the remains of countless myriads of animals 
are entombed in them, which lived and died at periods long ante- 
cedent to the creation of the human race, nay, more than this, 
that almost every grain of sand and particle of dust wafted by the 
wind, teems with organized matter. We have lying before us 
specimens of whitish earth which to the unassisted eye appears 
^but light chalky powder ; we have but to wet a little of it and place 
it under the microscope a*nd a thousand perfect forms are visi- 
ble. From the midst of a lump of chalk we have extracted a 
nodule of flint, and by the hammer have chipped off several thin 
slices ; one of these is now under the microscope by us, and we 
distinctly recognize two beautiful species of infusoria, as perfect 
and well defined as though now alive, and yet, these little beings 
have been entombed for myriads of years. What mighty changes 
have come over the face of our globe since the flinty sea encom- 



296 THE WORLD. 

passed them, and how few of the countless thousands of all that 
sea, have been preserved for the curious gaze of the student of 
nature. The thoughts which overwhelm the mind when con- 
templating the wonders of the universe, impress us with almost 
a feeling of sadness that creation is so vast we can never compre- 
hend the whole of it. The influence however, of scientific pur- 
suits upon the mind, is most beneficial, and the great lesson 
taught by science is, that our habitual ideas, and our first im- 
pressions are far from being nearest the truth. Indeed we have 
already observed in the first part of this work, that Astronomy 
begins by convincing us that the sun, which apparently is revolv- 
ing around the eaith, is in reality still, but that our globe is turn- 
ing daily on its axis, although apparently un moving. Geology 
in like manner begins with even more unpleasant truths, and 
convinces us that the present configuration of the continents and 
seas, so far from being the primeval condition of things, is but one 
of the various vicissitudes through which the world has passed. 
We are accustomed to consider the earth as coeval with man, 
and that but five or six thousand years have elapsed since their 
creation. Geology demonstrates that our present abode is of far 
greater antiquity, and the slightest examination of the crust of the 
earth will convince us, that the substances of which it is com- 
posed, are the results of accumulations or deposits extended 
through a long period of cycles. As we have already observed 
all the strata, with the exceptions of the igneous rocks, the granite, 
the gneiss, and the mica-schist systems, are fossiliferous, and it 
is highly probable that even these rocks are of sedimentary ori- 
gin, and once contained the remains of organic matter. The 
vast series of other deposits are the undoubted mineralized beds 
of primeval oceans, with occasional* interpositions of lacrustine 
or lake formed, and fluviatile or river deposits, the former rival- 
ing those of the vast Atlantic and Pacific, and the latter those of 
the immense inland lakes and rivers of the American continent. 
We do not find these mineralized beds or rocks, in all cases bear- 
ing the marks of quiet, but showing the agency of numerous dis- 
turbing influences, they have been upheaved and bent over; and 
broken through by the erupted and molten masses from beneath, 



ivilNKRALS AND FOSSILS. 297 

• 

which have flown up through wide chasms and overspread them. 
Intervals of unusual volcanic agency, have been succeeded by 
ages of tranquil repose, and these again succeeded by a revival 
of former energy. We see in all these vast changes the control- 
ing power of an Eternal Mind ; periods of time which man in 
vain endeavors to comprehend, have Witnessed continual exhibi- 
tions of creative power and wisdom. The diversified materials 
of which the earth is composed, have been elaborated into beauty 
and order, every object has its sphere of usefulness and action, 
and its period of existence is limited. We have never been able 
to perceive at all the grounds for the too hasty conclusion which 
some superficial philosophers have adopted, that the present per- 
fect system of organization is the result of a progressive develop- 
ment of inferior types of existence, and that the remote origin of 
all life is the monad or animalcule. 

It has ever been the attempt of man to penetrate beyond the 
ordinary boundaries, which nevertheless, like the almost impassi- 
ble barriers of a deep ocean surround him. Now with his heavens- 
directed tube, he speculates upon the former conditions of all 
worlds. Penetrating back to periods of time far beyond the dream 
of the geologists, he imagines the wisps of nebulous m-attei which 
in a clear night, with the most powerful glasses, he can just de- 
scry, and which appear as rare and light as the thinnest vapor 
which floats in the form of a cloud on a summer's eve, these he 
imagines slowly condensing, and gradually forming worlds. The 
geologist looks back to the remote and primeval ages when the 
first life appeared on our planet, and he uncovers with careful 
hand the imbedded remains of fragile plants, and shells, which 
have lain hidden in their stony beds for periods of time compared 
with which, our years dwindle to utter insignificance. 

The whole substance of our globe, at least so far as the solid 
materials which compose its crust are concerned, may be divided 
into two great classes, minerals and fossils. 

Minerals are inorganic snbstances, and are the products of 
chemical or electrical action. 

Fossils are the remains of organic substances imbedded in the 
strata by natural causes at some remote period* and these remains 



2§8 



THE WdRLD. 



are of the utmost importance in the eyes of geologists. If we 
examine the successive beds of water deposits in the various parts 
of our country we soon find that peculiar and characteristic fos- 
sils belonging to one locality. Or if we penetrate the earth to 
such a depth that we reach the strata, which at some distant 
place may crop out, or appear on the surface, as explained page 
184, we will then find the same fossil remains as would be 
found at the surface at that distant place. The inference which 
we naturally draw from this is, that if at different ages of the globe, 
when the successive strata were deposited, different races of ani- 
mals and vegetables flourished, then these fossil remains will 
enable us to determine with something like certainty, the relative 
ages of the strata which compose the various parts of a country, 
for it must be remembered that the rnineralogical character of 
most of these beds is the same, and many times no opinion 
whatever can be formed from this. Hence these remains have 
been appropriately termed the " Medals of Creation," and they 
afford to the geologist precisely the same evidence of the charac- 
ter of the period when they existed, and were deposited, as an 
ancient coin to the numismatist, of the character of the people* 
and the period when it was struck. Oftentimes a single coin or 
medal, is the sole remembrance which exists, to determine the 
date of a great event, and so a few bones, a shell, or a tooth, or 
track of a bird in the sand, are the sole memorials of peculiar 
types of existence of the primeval world. It would seem at first 
that from the very nature of the materials which compose most 
organic substances, that all traces of them would soon be oblit- 
erated. It is true that the soft and delicate parts of animal and 
vegetable organisms rapidly decay after death, yet in certain cases, 
their decomposition is arrested, and by a peculiar process every 
part is transformed into stone; thus, many of the most perishable 
vegetable tissues have been preserved, and even in the anthra- 
cite coal, which has been burned in the grate, distinct traces of 
organic structure can be observed under the microscope. The 
woody fibre of vegetables, the bones and teeth of animals, deeply 
imbedded in the earth, are thus preserved in some instances with 
wonderful accuracy and perfection. The perishable fleshy parts 



Organic remains. 2911 

of the animal of the Belemnite, a characteristic fossil of the 
Oolitic group, have been thus preserved in indurated clays, and of 
the cuttle-fish in limestones; The delicate impressions of plants 
of the various epochs stamped in the sandstones, shales, coals* 
and chalks, are presented with the utmost fidelity. The silicious 
shells of animalcules are every where abundant; in our own coun- 
try whole districts are composed of them; in Virginia, New Jer- 
sey, New York, Massachusetts, Michigan, and Iowa, and prob^ 
ably every state of the Union, their remains are more or less 
common. In a previous chapter we have admired the construc- 
tions of the coral-animal, and considered with a feeling of aston- 
ishment and wonder, the immense importance of the labors of so 
apparently helpless and insignificant a being; but what shall we 
say to the beds of rocks, composed of the remains of animalcules 
invisible to the eye ? yet of such are the pyramids built ! Not 
only are the carapaces, or shelly coverings, of these minute ani- 
mals preserved, but in many instances the fleshy parts of certain 
minute chambered shells are admirably preserved, imbedded in 
the heart of a flint nodule, and one familiar with such appearan- 
ces, can in the merest fragment of flint, detect various organic 
bodies. The variety of limestone called encrinital marble, is 
composed almost wholly of a peculiar stony animal called the 
Encrinite, and particularly abundant in the carboniferous, or 
mountain limestone, of the carboniferous group. A specimen 
from the Helderbergh Mountains near Albany, lies before us, 
compact and firm as though originally composed of crystaline 
materials. The ordinary observer can form but little idea of the 
amount of organic remains distributed throughout the various 
strata. 

In the following chapters we shall consider in order the three 
great epochs, or periods of the earth's existence as demonstrated 
from the study of fossil animal and vegetable remains. The first 
epoch commences with the granitic period, or period antecedent 
to the introduction of life, and ends with the carboniferous or 
great coal formation. The second period commences with the 
new red sandstone, and ends with the cretaceous or chalk system . 
The third and last period embraces what are termed the tertiary 



300 t'HJfi WORL& 

deposits. We would refer the reader to the chart on page 194, 
where these divisions will appear marked according to Dr. Buck- 
land, under the names primary, transition and secondary, and 
tertiary. It will only be possible to give a very superficial sketch 
of the probable condition of our planet during these several 
epochs, but we shall endeavor to convey a clear idea of the suc- 
cession of animal and vegetable life which so strongly character- 
izes them, so that the reader will be prepared to enter upon a 
more extended investigation. 

It is almost impossible even when writing upon ordinary topics, 
to avoid the use of technical terms, and perhaps legist of all can 
this use be avoided, when natural history becomes the subject. 
There is nothing of so much benefit, both in economising the 
time of the student,and in assisting his memory, as a correct and 
intelligible system. A well selected name, expressive of pecu- 
liar characters, or habits, or localities, conveys a multitude of 
ideas to the mind, which a common or vulgar name would en- 
tirely fail to do, for this reason we shall use the names generally 
applied by geologists to the several fossils, giving in all cases, 
their meaning or translation, whenever these words are derived 
either from the Greek or Latin. The word fossil, which wg have 
often used, meant originally, what was dug out of the earth, it is 
now however applied only to the remains of organic matter. 

The fossil animal kingdom may be divided into six sections. 

I. Infusoria, or Animalcules. The name infusoria is derived 
from the presence of many genera, or groups of species, in vege- 
table infusions, not easily observable without the microscope. 

II . Zoophytes, or Animal Vegetables, a term applied to corals 
and other animals supposed to resemble plants; the subdivisions 
of this group are, 

1. Amorphozoa, or animals of no regular shape like sponges and 

2. Polyparia, or many producing animals as the corals. 

III. Echinoderma, or spiny skinned animals, subdivided into, 

1. Orinoidea, or Encrmiial, i. e. lily or cup -shaped animals. 

2. Asteria, or ^tar -formed, like the- star-fish, 

3. EcHitfiOA, or spiny animals, like the sea-ur-chi», or sea-egg. 



/ 



OIVISR3N ©F THE ANIMAL KINGDOM. 301 

IV. Mollusga, or soft bodied animals, destitute of bones, un- 
der this head are embraced the fossil shells. 

1. Bivalves, or consisting of two pieces like the oyster and clam. 

2, Univalves, or consisting of one shell like the snail and peri- 
winkle; these latter are the true molluscs, and are of a 
higher degree of organization than the former, possessing 
a head and eyes, of which the former are destitute. 

&. Chamber ld shells like the nautilus, including both the tes- 
taceous or shell covered genera, and naked molluscs as the 
cuttle-fish. 

4. Cirripedia, or hairy-footed animals, like the barnacle. 

V. Articulata, or jointed animals, comprising, 

1. Annelata, or ringed animals, like the red blooded worm. 

2. Insecta, or insects, i. e. having the body nearly divided in 
two, like the wasp and fly. 

3. Arachnida, or spiders. 

4. Crustacea, having a cr testaceous skin like crabs and lobsters. 

VI. Vertebrata, or animals having a spinal column or back- 
bone, subdivided into, 

1. Pisces, or fishes. 

2. Reptilia, or reptiles. 

3. Aves, or birds. 

4. Mammalia, or animals giving suck. 

The animal kingdom is divided into the above great classes, 
and these are subdivided into avast number of species, each being 
characterized by some peculiar and distinguishing mark. The 
expert anatomist can often from the mere inspection of a tooth, 
or a claw, determine the character and habits of an animal. Of- 
tentimes this, or even a foot-print in the sand, is all that remains 
of some now extinct creature, yet by analogy, instituting a rigid 
and close comparison with existing species of the same gen- 
era, the peculiarities are distinctly made out, and many remarka- 
ble facts are brought to light. We now proceed to consider the 
probable condition of our planet during the stages of existence 
before enumerated. 



302 THE &&BLX.&. 



€ EI AFTER XIII, 

The first Epoch, 

*' The land that hath no summer flowers* 
Where never living creature stood; 
The wild, dim, polar solitude: 
How different from this land of ours ! " 

Mary Hoiciti. 

The first great period, commences with the granitic and ends 
with the coal formation. Beneath the most ancient deposits lies 
a crystaline rock which, under the name of granite, is familiar to 
to- every one. Lofty mountain chains, sometimes rearing their 
Alpine summits far beyond the limit of perpetual snow, look 
down in solitary grandeur upon the scenes below. The hardesfi 
and most indestructable of all rocks, it seems fitted for the foun- 
dation or superstructure of the entire mass. Occasionally it is 
found of a more recent origin, exhibiting the appearance of hav- 
ing been ejected after the deposition of the newer strata; probably 
the result of intense heat acting under great pressure. We may 
suppose then that there was a time, "the beginning," when a 
globe existed having alternations of stone and water, no soil was 
upon its surface, which was a bare rock, presenting innumerable 
rugged peaks; not a sea- weed floated in the waters, nor a lichen 
grew on the rock; no sound was there except the monotonous and 
angry dash of the waves upon the bare and desolate coast. But 
even then, the atmosphere,perhaps surcharged with carbonic acid, 
was actively engaged in crumbling down the barren rocks, and 
we may suppose that the waves and the winds urged their com- 
bined force as now; the fragments of granite thus torn off, were 
deposited in the bed of the ocean, and we find them compacted 
under the name of gneiss. If during this action, the felspar was 

artlv decomposed, then the quartz or silex, would be deposit- 



BASALTIC COLUMN S, 



303 



ed alone, and subsequently the felspar and mica, either in the 
form of mica schist, which is composed of layers of mica and 
quartz, or slaty rocks without fossils; these are the strata which 
lying immediately upon the granite, and presenting marks of 
aqueous deposition, yet partake more or less of the crystaline 
character of the primitive rocks. During all the long period of 
the deposition of these rocks, formed from disintegrated granite, 
not a living thing moved, either on the dry shores or in the deep. 
Perhaps a few animalcules existed in the clear waters, but we 
have no distinct traces of them; all was silent, the stillness of ab- 
solute death. During this period however, great volcanic con- 
vulsions occurred, the yet soft masses of gneiss and schistose 
slates were upheaved, and in many cases rent open and molten 
masses of granite and basalt flowed through. The metals, melted 
by the intense heat, were injected into the narrow fissures, and 
innumerable dykes and veins were formed. In some instances 
the masses of melted trap rock have crystalized upon cooling, in 
regular hexagonal prisms. Such are the columns which compose 
the celebrated Fin gal's Cave, exhibited in the wood-cut below. 




Directly associated with the contorted masses of mica schist to 
which we have just alluded, there is a coarse slaty rock, exhibit- 
ing still more clearly the marks of aqueous deposition, but by far 
the most interesting circumstance connected with this deposit, 
is the first appearance of animal life. We must consider with 
no little interest, the fossil remains of these early rocks; among 



304 THE WOULD. 

them are found peculiar species of shells, and a few corals, but as 
yet, nowhere throughout the whole world, in this immense de- 
posit called the Cambrian, (page 191), has the least fragment 
been found referable to a fish; nor any traces of aquatic plants, 
except a few sea-weeds; nor vertebrated animals* It is therefore 
pretty evident, that at this time, either they did not exist, or if they 
did, it was in extremely small numbers. We find the lowest or- 
der of organization here developed, in the remains of a zoophyte, 
or animal plant figured below, which is analagous to the sea-pen, 




and termed by Mr. Murchison, who has investigated with great 
care, this series of rocks, graptoliUs, from the peculiar markings 
of the stone; these were probably formed by an assemblage of a 
vast number of individual polypes, each having a separate exis- 
tence, but yet connected with the general mass, they are found 
in great abundance in the United States. There are also many 
species of coral common in the most ancient rocks, and similar 
in most respects to those now existing in the Indian Seas. The 
low organization of these coral polypes has probably enabled them 
to survive all the changes through which, so often the w T orld has 
passed, and we find them at the present moment as busily em- 
ployed as in the earliest periods of the earth's existence. The 
Silurian rocks are extensively developed over the whole world so 
far as geologists have been enabled to explore. The immense de- 
posits of calcareous flags, sandstones, shales, and limestones, 
furnish our most valuable stones for economic purposes. As we 
advance upwards in the series of deposits we find a marked 
change not only in the mineralogical character, but in the num- 
ber and form of the organic remains. Among the peculiar ani- 
mals which flourished at this stage of the world's existence weie 



ENCRItflTRS AND TRIKOBITF.S. 



305 



the Crinoidal, or lily-shaped animals, so called from a fancied re- 
semblance to a lily, they are somteiines termed Encriniles. We 
here figure two specimens, one closed and the other open. There 





are a very great many varieties of encrinites, some of the most 
beautiful occur in the new red sandstone group, figure 1, is 
called the pear encrinite, fig. 2, the tuberculated; they consist es- 
sentially of a stony case, supported on a slender jointed stalk, 
and are found in all positions and in immense numbers, but they 
are of a much higher organization than the coral polype. An- 
other very peculiar fossil of this epoch is the trilobite, so called 
from the body consisting of three distinct lobes. We here repre- 
sent one of these animals; thev are found in abundance in the 




older strata, and of many distinct generic forms; they probably 
possessed short legs and were destitute of antenna?, the eye how- 
ever, was the most remarkable feature. It was immovable, but to 
compensate for this it was exceedingly prominent and provided 
with many hundred lenses, precisely similar to the eye of the 



30G 



THE WORLD. 



dragon-fly, and the house-fly. Among the molnscs, or soft 
bodied animals, we find one very common and characteristic of 
this period, but now entitely extinct, it belongs to the same fami- 
ly ccphalapoda, i. e. having the arms or feet near or upon the 
head, as the nautilus, and is called the orthoceratite, or straight 
horned animal and is figured below, nothing is known of these 




except the fragments of their former habitations, some of them 
are slender and pointed, others nearly straight, and they are oc- 
casionally found of great size. Such were the inhabitants of 
{he globe during its early periods, while yet no fishes swam in 
its waters, or animals roved in forests upon the shore. Trilobites 
swarmed in innumerable multitudes; the crinoidal animals were 
attached to every fragme t of rock; and the voracious cephala- 
poda roamed through the deep. Day and night then as now suc- 
ceeded each other, and year after year passed on, but who can 
tell, or who can estimate the ages which rolled away from the 
commencement of the period we have been considering to the 
close of those immense deposits called the Silurian. But the 
dawn of a new era was now commencing, and the great and im- 
portant natural class of fishes were about to be introduced, though 
with such marked peculiarities and singular forms, and so differ- 
ent from any now living that they almost seem allied to the crus- 
taceans, or to the reptiles. One of the most singular, with 
long bony fins, is called the Pterichthys Cornutus, or horned wing- 
ed fish. It was of small size, the head and body being covered 
with strong plates of bone coated with enamel. Another singu- 
lar fish called Cephalapsis, or buckler-headed, possessed an enor- 
mous buckler head, similar to the cephalic shield of certain trilo- 
bites. It has been compared, and not unaptly, to the crescent 
shaped blade of a saddler's cutting knife, as will be seen on ref- 
erence to the engraving on the following page. 

There are many other varieties or groups of fishes belonging 



GANOID FISHES. 



to this period which we cannot name here, but most of them be^ 
Jong to the two great classes designated by M. Agassiz, the Pla- 




eoid, or plated; and the Ganoid, or shining, or enameled. The 
irst class, is at present represented by the sharks and rays, and 
the second by the sturgeon and bony pike. The former or Pla- 
<eoid, were first introduced, but were comparaiively small and 
feeble, but the latter, during the Devonian, or old red sandstone 
period, (see page 190), were very abundant It is somewhat re- 
markable that this group of fishes is now represented by only two 
species, the American Gar-pike and the Birchir of the Nile; no 
less than sixty distinct species being found in the old red sand- 
stone. No traces however, of those groups of fishes, now so 
abundant, are found in these strata. Leaving this remarkable 
period, when the waters teemed with formidable and singular 
shaped fishes, we find the commencement of a new epoch in the 
appearance of an immense deposit of carbonate of lime, in the 
form of the carboniferous or mountain limestone, and the varie^ 
gated marbles; imbedding a remarkable number of vegetable fos- 
sils, which indicate not only the presence of land, but the exis- 
tence of a luxuriant and tropical vegetation. The carboniferous 
limestone, is in many cases the result of the If oors of the coral 
insect, indicating the presence of a shallow se i- bottom and warm 
temperature. Immediately in contact wit'p the coraline lime- 
stones is a coarse sandy conglomerate used for milistones, and 
called the mill-stone grit, which is succeeded by strata of shale 
and sandstone, with occasional seams of coal; after which, follow 
the coal measures, so called, being large deposits of bituminous 
coal. But little doubt can exist as to the vegetable origin of al! 
eoal; it is true that the most perfect bitemino^s coal has under*.- 



3Ud the world, 

gone a liquelactiou which has destroyed its organization, but in 
the slaty coals and the shales, traces of cellular tissue are obser- 
ved, and the peculiar spiral vessels and dotted cells, indicating 
the coniferous or cone-bearing wood, We must therefore con- 
clude that these beds of coal, although mineralized, and almost 
crystaline in their appearance, are entirely of vegetable origin. 
Among the fossils of the coal there are a great variety of ferns, and 
some of them of very elegant forms. We here give figures of 
two species, fig. 1, is from the coal shales of Ohio, called the 




2 1 

Pecopteris S'dlimani, or Silliman's embroidered fern; and fig. 2, 
the Sphmopt&ris, or wedge -leafed fern; from the coal shales 
Silesia. Besides the fern tribe, which in the ancient world seems 
to have been much more largely developed than at present, we 
find gigantic specimens of the Calamite, similar in all respects 
to the common reed growing abundantly in our marshes and 
called Equis&lmn, or marestaiL 

Notwithstanding the extensive beds of coal found everywhere 
over the globe, no trace or fragment of quadruped, bird or rep- 
tile, has been discovered. The immense forests of aborescent 
Or tree ferns, and coniferous trees with their rich and luxuriant 
begetation, were desolate and silent; no reptile crawled over the 
damp ground, no bird made a nest among the green foliage, no 
ound broke the primeval silence, which for ages shrouded the 
thick forests; silently they sank down beneath the waters, and 



CLOSE OF THE FIRST EPOCH. 309 

in the lapse of ages other strata enveloped them, and preserved 
the forms of their delicate leaves, and the markings of their 
trunks and stems, for the inspection of long succeeding ages. 
But all this time the sea was alive with its multitudes of corals, 
of echini, trilobites, and peculiar cephalopods, and fishes. It 
was during this epoch, that the ganoid fishes were most highly 
developed, and innumerable sharks of all sizes abounded in the 
carboniferous seas. 

We have now arrived at the end of our first epoch, just before 
the introduction of reptiles. There seems in some respects to 
have been a progression in organization, and yet, not such as to 
support the view, however plausible, of the agency of an inferior 
type of organization in introducing a higher group. The corals 
and the encrinites still remained with but little change, but the 
trilobites were nearly extinct, the cephalapodous animals, retain- 
ing till now the straight and elongated form of the orthceratites, 
assumed the spiral form of the goniatite. The small fishes of 
the early epochs gave place to large and voracious species, pow- 
erful swimmers and insatiably voracious; vast tracts of country 
were settling down, and the rich and rank vegetation, which cov- 
ered the land at the time of the coal epoch, was prepared for the 
first stage of its change into coal. During all this period, we 
must not fail to note the entire absence of all the grasses, which 
now form so prominent a portion of existing plants ; indeed, 
the whale face of the globe, was so entirely different from its 
present appearance, that could we now behold it, we might 
realize that we were looking upon another planet. It is not for 
us to discuss the question of the length of time necessary to ac- 
complish all those changes which the globe has passed through, 
or to speculate upon the distinct efforts of creative power ex- 
hibited throughout those countless ages. It is sufficient for us 
to know that myriads of beings, dissimilar to any now existing, 
or only remotely connected, flourished perhaps for thousands of 
years, when suddenly they disappeared, and quite as suddenly 
new forms replaced those lost. There can be no way of account- 
ing for these changes in the forms of animal and vegetable life, 
except by the direct interposition of a creative power. 



310 THE WORLD. 



CHAPTER XIV. 

The second Epoch. 

"And later yet the sea o'erspread 
The sj3ot where now we walk ; 
And this was once an ocean's bed, 
The ocean of the chalk." Anon* 

The epoch now to be considered, is in many respects the most 
interesting, as it is certainly the most abundant in its fossil re- 
mains. In our present volume we can only glance at the char- 
teristic features, leaving wholly untouched those minor details, 
which often make the most interesting part of a history. We 
can therefore only hope that the reader will make a beginning 
here, but search elsewhere for more extended and minute infor- 
mation. Immediately above the coal measures, lies a coarse sandy 
deposit, which appears to be the ruins of some more ancient rock, 
consolidated by pressure and the infiltration of water impregnated 
with iron. The shores of the previously existing lands, seem to 
have gradually been depressed, forming vast beds of coal; upon 
these, the beds of sand and marl were loosely and rapidly de- 
posited, and are not exceedingly rich in their fossil remains. 
There is however, one interesting and remarkable fact connected 
with these deposits, and that is, distinct tracks of reptiles and 
birds; to these we shall allude again presently. The lowest 
member of the new red sandstone group is the magnesian lime- 
stone, so called from having a considerable portion of carbonate 
of magnesia mixed with its carbonate of lime; it is a stone ex- 
ceedingly valuable for building purposes. This limestone con- 
tains a few fossils, corals and shells, and occasionally a few frag- 
ments or whole skeletons of fishes. The fishes are all remarka- 
ble for a peculiar structure of tail characteristic also of the fishes 
of the older strata, this structure is called by M. Agassiz the bete- 



DOSSIL FOOT -STEPS. 



311 



rocercal, the tail being unequally lobed as in fig. 1, which is the 
tail of the shark, and the vertebral column running along the 
upper lobe. On the other hand, in nearly all the living species, 




the tail is homocercal as in fig. 2, which is the tail of a herring, 
the vertebral column not extending to the upper lobe. 

We have remarked that the first tracks^of reptiles are met with 
in this system of deposits. Below we represent the appearance 
of these footprints as observed in England and Germany. It 






will be perceived that there are two impressions which always 
accompany each other, and they are not unlike the human hand, 
hence the animal was named cheirotherium or hand beast. This 
animal was for a long time supposed to be allied to the kangaroo, 
and like it a marsupial, i. e. having a pouch in which to carry its 
young; but more recently Prof. Owen, from a careful examina- 
tion of teeth and other bones found in the new red sandstone, has 
determined it to belong to the class of batrachians, or frogs, toads, 
salamanders, &c, and from the peculiar structure of its teeth, 
he has given to this genus the name labyrintlwdon, or labyrinth 
tooth. Besides the tracks just described, are found those of tur- 
tles, of a little lizard with a bird -like beak, and the trails of 
molluscs, and vermes, and the ripple marks of the ancient seas. 
By far the most remarkable tracks occurring in the new red sand- 
stone group, are those of gigantic birds, the foot-prints being sev- 
enteen inches long, and the stride of the bird from four to six 
feet. It is somewhat remarkable that nearly all the fossil foot 



312 



THE WORL©« 



marks yet discovered, occur upon some member of the new red 
sandstone group. On the same stone are impressions of rai« 
drops. "It is a most interesting thought,'* observes Prof. 
Hitchcock, " that while millions of men who have striven hard 
to transmit some trace of their existence to future generations, 
have sunk into utter oblivion, the simple footsteps of animals, 
{hat existed thousands, nay, tens of thousands of years ago, 
should remain as fresh and distinct as if yesterday impressed; 
even though nearly every other vestige of their existence has 
Vanished. Nay still more strange is it, that even the pattering 
of a shower at that distant period, should have left marks equally 
distinct, and registered with infallible certainly the direction of 
the wind." When these foot prints were first discovered their 
enormous size seemed an insuperable objection to the opinion that 
they were bird traeks. But recently in the island of New Zea- 
land, the bones of an immense wingless bird have been found to 
which the name Dinornis, or terrible bird, has been given. Be^ 
low is an outline representing the size of this extraordinary ani- 
mal compared with a man. 




Immediately above the new red sandstone in some parts of the 



THE PLESIOSAURUS. 



313 



world, but particularly in England, is deposited a fine sandy and 
marly stratum, consisting of distinct layers with occasional lime- 
stones, and exceedingly abundant in remarkable fossil remains. 
To this tne name Lias has been given, and the reptilian remains 
imbedded in it are the most magnificent objects of the Creator's 
hand. During the deposit of these muddy beds which were un- 
favorable to the growth of corals, we find but few traces of these 
animals, but on the contrary the crinoidea, already alluded to, 
were developed in singular and 'beautiful forms, and also very 
peculiar forms of the cephalapodic group. Among the marine 
reptiles of the epoch we are now considering, two are particular- 
ly noticeable. The Plesiosaurus, or almost lizard, and the Iclithy- 
osaurus, or fish lizard, Below we represent the plesiosarus, which 
possesses a head small, and lizard -like, with teeth like a croco- 




dile, a neck of enormous length like the body of a serpent, and a 
back and tail having the proportions of an ordinary quadruped. 
It is furnished with four paddles, and is supposed to have inhabi- 
ted the shallow waters; darting by means of its long neck, sud- 
denly at the fish which came near it. The largest complete spe- 
cimen of the plesiosarus yet discoveredis about eighteen feet in 
length. Fierce and voracious as this animal undoubtedly was, 
yet it had an enemy in the ichthyosarus represented in the follow- 
i ng wood cut. This formidable marine reptile sometimes attain- 




ed to a length or thirty or forty feet, and like the whale possessed 
a smooth and naked skin. The eyes were enormously large and 
provided with bony plates, or divisions arranged around the pupil. 
There are instances where the diameter of the orbit is eighteen 



314 THE WORLD. 

inches across. The jaws are long and furnished with sharp coni- 
cal teeth, resembling those of the crocodile, and like them re- 
placed continually, as they become worn, hy new ones ; the fins 
or paddles were four. Both these remarkable animals, now en- 
tirely extinct, are figured in the frontispiece of the present vol- 
ume, which is designed to represent the condition of our globe 
during the period we are now considering. 

Above the lias shales is a deposit which seems to indicate great 
changes in the organic world, caused by the elevation of wide 
tracts of country over certain portions of the globe, attended with 
numerous depressions in other parts, and the strata deposited 
during these movements seems to have formed the bed or final 
depository of many successive races of beings. The name Oo- 
lite given to this group of deposits signifies egg-like stone, be- 
cause it is formed of small egg-like grains, like those comprising 
the roe of a fish, the nucleus of which, on microscopic examina- 
tion, appears to be some minute organic substance, usually a frag- 
ment of coral, or a shell. To this class belong the so-called 
Oxford and Kimmeredge clays, and the Jura limestone, since the 
mass of the Jura mountains in France is of the oolite formation. 
During this period, an immense number of marine animals flour- 
ished, most of which are now entirely extinct, among them are 
peculiar corals, star-fishes, and sea-eggs or echini. Below we 
give a representation of a very perfect crustacean, similar to the 




lobster, from the oolite clay of Yorkshire, England. The fossil 
remains of insects are also common in these strata, and very pe- 
culiar and beautiful forms of ammonite^ which s§ems to have 



THE BELEMNITE. 



315 



been most perfectly developed in the lias seas. We have before 
described a cephalapod called the orthoceratite, (page 306), "sub- 
sequently we find this animal displaced by one with a curved and 
somewhat angular shell during the carboniferous formation, still 
later during the deposition of the lias and oolitic beds, we find 
another change under the form of the ammonite; at the same 
time the nautilus, a well known cephalapodous animal, closely 
related to the ammonite, was -likewise abundant. The nautilus 
still inhabits our tropical seas, and unfolds its fleshy sails to the 
gentle breezes, but long since the ammonite has been extinct. 
Another of the same class or group of animals, and which is now 
represented by the cuttle-fish, is the animal of the belemnite. 
The fossil called the belemnite from its resemblance to a dart or 
javelin, is not uncommon, and is found of various lengths and is 




sometimes called by the singular names of the devil's toe-nail, 
thunderbolt, &c; the general appearance of the fossil is howev- 
er as represented in fig. 1, and perhaps no organic remains have 
ever caused more ludicrous mistakes, or given rise to more fanci- 
ful theories. It is the internal skeleton of an animal very much 
like the cuttle-fish, and represented in fig. 2. From the fossil re- 
mains, this animal appears to have been exceedingly large and 
formidable, preying upon the smaller fishes and reptiles, it was 
furished with eight long arms, each provided with from fifteen to 
twenty hooks; the eyes were large and the jaws powerful. Like 
the common squid, it seems to have been provided with an ovsil 
sac, containing a dark fluid, ejected by the animal when alarmed 
in order to discolor the water and facilitate its escape. During 



316 THE WORLD. 

this period the plesiosaurus, and the ichthyosaurus abounded, and 
in addition we find another marine monster rivaling the largest 
whales in size, possessing webbed feet armed with strong claws. 
The flora of the carboniferous period, we have observed, con- 
sisted mostly of ferns, and large coniferous trees, of gigantic di- 
mensions, and of calamites, and numerous other plants the 
exact nature of which is not yet determined; but in the lias and 
oolitic formations an entirely new race of plants covered the earth. 
The ferns, which formerly constituted two-thirds of the entire 
species known, were greatly diminished, and the calamites and 
palms all disappear. Coniferous plants were still very common, 
but of different species from those of the earlier epochs, and 
plants analagous to the CycadeeB and Zamias of the tropical re- 
gions seem to have replaced the ferns. The wood cut will give 
a tolerable idea of the character and appearance of the flora of 




the oolitic period. During this Age of Reptiles, as it has been 
termed, one of the most marvellous beings, and which for along 
time caused no little speculation and discussion among philoso- 
phers, flourished in considerable numbers. It has been termed 
the Pterodactyle, or wing-toed animal. (See next figure). This 
flying reptile, possessing the head of a bird, the wings of a bat, 
and the body and tail of an ordinary mammalian, appears to be a 



THE rrjuu>DACi YI.R. IU 7 

sort of connecting link between the three great groups, reptiles. 




birds, and mammals. It seems to have been capable of walking 
with ease upon the ground, of perching on trees, and of flying 
swiftly through the air. The teeth of the pterodactyle are long, 
pointed, and slender, from twenty to thirty in each jaw, and like 
the crocodile replaced by new ones when worn. — While the cal- 
careous oolitic beds were being deposited in the sea, there seems 
to have been in some parts of the world, but particularly in the 
southern part of England, immense rivers, with extensive estu- 
aries flowing over vast tracts of countries, and bearing down 
upon their waters and imbedding in the mud and silt of the shoal- 
ing estuaries, the remains of land plants and animals, and fresh 
water shells. To the beds or deposits thus made, the name 
Wealden has been given, (see page 183). With the exception 
of the plants of the coal epoch, this deposit is almost the sole evi- 
dence of the ancient land and its inhabitants. It is somewhat 
remarkable that among all the previous deposits no trace of any 
true quadruped has been found, all the remains belong to marine 
or land reptiles, and up to the time of the Wealden formation no 
traces except the few tracks on the new red sandstone, are found 
of birds. Dr. Mantell, who has so successfully investigated the 
geology of the south-east of England, has however in the latter 
named strata, discovered many fragments of bones supposed to 



318 THE WORLD. 

belong to birds allied the Heron. Among the reptiles character- 
istic of this deposit the most remarkable is the Iguanodon, so 
called from the resemblance of its teeth to those of the Iguana, 
a recent West Indian lizard. This gigantic suarian, or lizard, was 
upwards of 70 feet in extreme length; the circumference of body 
14J feet; length of tail 52J feet; and of the hind foot 6J feet. In 
the British Museum, is a thigh bone of an Iguanodon, which is 3 
feet in length, and eight inches in diameter. We cannot easily 
conceive of a reptile of such hu^e dimensions: surpassing in 
height the tallest elephants, and far greater in bulk than any 
known living animal. A reptile of the same class, called the 
Hylaeosaurus, or lizard of the Weald, was likewise discovered by 
Dr. Mantell; in dimensions it was somewhat less than the igua- 
nodon, and armed with a row of spiral protuberances, and scaly 
plates. 

During the deposit of the chalk, a vast multitude of fishes 
swarmed in the waters, among these were immense sharks, 
whose remains are plentifully found. How different the scenes 
then enacted, both on land and in the sea, from now. While 
upon the land, gigantic reptiles prowled through the dark woods, 
or along the chalky shores, covered with alligators and turtles; 
and the pterodactyle glided swiftly amid the dark foliage in pur- 
suit of its prey ; the icthyosaur, the plesiosaur, and voracious 
sharks roamed through the deep, devouring multitudes of smaller 
animals. Upon the surface of the waters, the nautilus and 
ammonite siill sailed, and the sea egg rolled over the smooth bot- 
tom. Then, as now, the coral insect toiled on, and thousands of 
encrinites waved their flexile stems in the heaving waters 
Scenes like these, for ages, were witnessed upon the face of our 
planet, but we cannot begin to estimate the lapse, not of years or 
centuries, but of myriads, ere the change came which swept 
them forever from among the living things of earth, entombing 
them for memorials of those remote ages, which should tell in 
language too plain to be misunderstood, that many times, since 
the earth first commenced its revolution around the sun, changes 
have passed over its surface which would be more than sufficient 
to sweep away every living thing which now moves upon it 



THE THIRD EPOCH. 



319 



CHAPTER XV. 

The Tertiary Period. 

•' Yes ! Where the huntsman winds his matin horn, 
And thecouch'd hare beneath the covert trembles; 
Where shepherds tend their flocks, and grows the corn; 
Where Fashion on our gay Parade assembles — 
Wild Horses, Deer, and Elephants have strayed, 
Treading beneath their feet old Ocean's races." 

Horace Smith. 

We are now to consider the last great epoch, called the tertiary 
period, commencing immediately after the deposit of the chalk, 
and ending with the appearance of man. The tertiary strata 
consist of a vast and varied series of deposits, fluviatile, lacrus- 
tine, marine and volcanic, but they are all deposited in hollows 
or depressions, usually of the chalk, and occasionally cf the older 
rocks, and afford distinct evidence of important changes in the 
relative level of land and sea, during the period in which they 
were deposited, and they likewise show that volcanic agency was 
developed at this period on a vast and magnificent scale. From 
the remains entombed during this epoch, it is pretty evident 
that the climate of the ancient world was much milder than at 
present. Be this as it may, it is a fact indisputable, that not only 
the bones of hyenas, bears, lions, and tigers, are found in coun- 
tries where now they could not live, but also several varieties of 
palms and pines ; and even as far north as the 70° of latitude, 
the remains of the elephant and rhinoceros are found imbedded 
in the ice. During the tertiary epoch, the Ganoid and Placoid 
groups of fishes, so characteristic of the earlier deposits, were al- 
most extinct, the latter class being represented by a few sharks 
and rays, while by far the greater number were allied to existing 
species. The remains of birds; skeletons, feathers, and even their 



320 



THE WORLD. 



eggs, are found in good preservation — they are allied to present ex- 
isting species. On the island of New Zealand, an immense num- 
ber of fossil bones of birds have been found ; we have already al- 
luded to one of these, the Dinornis, page 312; the beak of this 
bird was shaped like a cooper's adze, and admirably adapted for 
tearing up roots ; they were, as Dr. Mantell remarks in a letter to 
Prof. Silliman, " glorious bipeds, some ten or twelve feet high." 
In the tertiary strata of the Paris basin, Cuvier found the remains 
of several thick skinned animals allied to the tapir, and of others 
forming a connecting link between the tapir and the ruminants, 
or animals chewing the cud — some of these were of very pecu- 
liar forms. A remarkable animal, characteristic of the middle 
tertiarj* period, was the Deinothcrium, or terrible beast, figured in 
the engraving below This huge animal dwelt probably in 




marshes and swamps, and was nearly twenty feet long ; the legs 
are supposed to have been nearly ten feet in length, the head was 
of proportional size, and furnished with two large tusks fixed in 
the lower jaw, which probably, served the purpose of pickaxes, to 
dig out the roots upon which it fed, and perhaps to anchor it by 
the side of the bank at night. In Russia and Siberia, remains 
of the elephant and rhinoceros have been found entombed in ice, 
together with birch trees, far beyond where even stinted bushes 
now grow. The tusks of the fossil elephants are found in the 
high hills above the sea level, in clay and sand frozen as hard as 
a rock, and increasing in abundance as we proceed north. For 
about a century they have been brought away in immense num- 



FOSSIL ELEPHANT* 321 

bers, yet with no perceptible diminution of the stock ; doubtless 
many of these animals were drifted dowu towards the arctic seas 
by the immense rivers which flow northward into the icy ocean. 
The subjoined figure represents the skeleton of the celebrated 
elephant discovered by a Tungusian fisherman, in the year 1790, 
in the banks of a river in Siberia, in which it had been frozen up 
for ages. The skin of this animal was of a dark grey color, and 




covered with reddish wool. The two tusks, together, weighed 
three hundred and sixty pounds, and the head alone, four hundred 
and fourteen pounds ; the flesh of this antediluvian was in such 
perfect preservation, that the dogs, white bears, wolves and foxes 
fed upon it. The eyes were well preserved, and the pupil in one 
of them could be distinguished. The fossil Siberian elephant 
differed but little from the one now inhabiting India, except in its 
wooly covering ; its food was probably twigs and branches, in pur- 
suit of which, herds of these gigantic quadrupeds probably mi- 
grated far north. The remains of elephants are very widely dis- 
tributed ; they are found in England and various parts of Amer- 
ica; the teeth of the elephant maybe readily distinguished from 
those of the mastodon, another large hebiverous animal belong- 
ing to this period, by a peculiar structure w T e will now describe. 
We here represent the teeth of the recent and fossil elephant ; a 
the African, b the Indian or Asiatic, c the Siberian or fossil. In 
the first variety, (a) the enamel is arranged in lozenge-shaped 
figures, and in the second ( b) in narrow transverse bands, very 



322 THE WOkLft. 

similar to the fossil species c; these teeth are composed of three 

/toss 




different substances ; the enamel, exhibited by the white loz- 
enges or bands, and which extends quite through the tooth to the 
roots ; the ivory inside of the lozenges, and the crusta peirosa or 
stony crust outside. The tooth of the mastodon represented be- 
low, consists of ivory and enamel only ; the enamel being spread 




over the crown of the toolh, its structure is similar to that of 
the hog and hippopotamus, fitted for bruising and masticating 
crude vegetables and roots. The bones and teeth of the mastodon 
are found all over North America, and many entire skeletons 
have been exhumed, in some of which, the remains of branches 
and twigs undigested have been found. The remains of these 
animals are particularly abundant in those marshy tracts, abound- 
ing in salt and brackish waters called licks. The mastodon was 
not unlike the elephant, but was somewhat larger, and probably 



the Megatherium. 



323 



much more powerful. While iu England and various parts of 
the eastern continent, the elephants were congregated in im- 
mense numbers, and the plains of North America covered 
with herds of mastodons, another and more singular animal, 
allied to the sloth, lived in the forests of South America ; we re* 
fer to the Megatherium, or great beast* In the museum at Madrid, 
there is a perfect skeleton of this animal, whose massive propor- 
tions strikes the beholder with astonishment ; it is represented 
in the wood-cut below, and the proportions will be recognized on 




comparing the figure with that of an ordinary sized man, drawn 
to the same scale. Its length is nineteen feet, breadth across the 
loins, six feet, and height, nine feet. The feet of the hind legs 
set at right angles, as in the bear; the heel projects behind, fifteen 
inches, and the toes, armed with long claws, about twice that dis- 
tance forward ; so that a proper base is afforded for the support of 
the immense body. The teeth of the megatherium were con- 
stantly renewed. This apparently unwieldy animal is allied to 
the sloth, but differs from it in the immense strength and mas- 
siveness of its posterior portions. It is supposed they fed upon 
the foliage of trees which they were enabled to uproot by their im- 
mense strength. This idea is confirmed from the fractures of the 
skull observed iu some of the specimens. Contemporary with 
the megatherium, were several other allied species, which ranged 
through the luxuriant forests of South America, while in England 



324 THE WORLD. 

were herds of deer and wild elephants. In Ireland* the fossil re- 
mains of an enormous deer, surpassing the largest elks in size, are 
found imbedded in the peat bogs. The expanse of the horns in 
some of the specimens is sixteen feet. There is reason to believe 
that this animal, though now entirely extinct, existed after the in- 
troduction of the human race, since skulls have been found frac- 
tured in front, as by the blow of some heavy weapon, and asso- 
ciated with artificial remains. The small Irish ox, or bison, 
was probably identical with the auroch of Lithuania, which is 
only preserved from utter extermination by a stringent ukase of 
the Czar. At the same time, most of the existing species of ani- 
mals and vegetables flourished in great numbers. The earth wns 
teeming with life and fitted for the ^habitation of man. The va- 
rious races which from time tostime succeeded each other on our 
planet, had performed their allotted tasks. The whole system 
uniformly and without interruption, seems to have been matured. 
The light soil deposited upon the harder rocks, and in the hollows 
of ancient lakes, was gradually elevated, forming the present 
'continents and islands. How long the present stage of the earth's 
existence may last, no one can pretend to answer. In all the 
changes which have heretofore swept races of highly organized 
beings from the face of the globe, we see the quiet action of laws 
now in force ; no sudden catastrophe is needed, but silently the 
change goes on. 

" The Earth has gathered to her breast again, 
And yet again, the millions that were born 
Of her unnumbered, unremembered tribes. ,, 



r *^0 V 




^r^w 






^°- 



J> 










: _/ °- 






^s 



j o «, v "* < \y o, * o « x ^ 

° * V ,. * * o /■ % 






J „ <T ^ v * ■ay . « » ■» -op- 



^\: 





<£ ■*>■ - 




/% ^ lffli 



%.<* 








/ I - 



4> 













- K * n - ■ %- \> ,. V * , •*» ° 









<^<**^ 






s J? 



•<* 




tt\<& 






r* V 






<&? 







V % ^ 



o°\- 



^ ^ *, 






ay v: 



^ 




^ 













^ 



Q».% 



* 10 



fV <?* 



(0>^ 












. % ^ 



^ 











o$? 



cS v 






'^o' 5 



^ ^ o ^Wv^ J- ^ <3ft z ^ 



.•ft^ 



o. 



r ^ .^ 




^o^ 



± -OS 



$> % ", 





° 003 K9 984 8 






m\.:; 






1 ■ K 



■ 



1 



